Merge branch 'master' into patch-1

Gemfile

@@ -38,7 +38,7 @@ gem 'rqrcode'
 gem 'twitter-text'
 gem 'oj'
 gem 'hiredis'
-gem 'redis', '~>3.2'
+gem 'redis', '~>3.2', require: ['redis', 'redis/connection/hiredis']
 gem 'fast_blank'
 gem 'htmlentities'
 gem 'simple_form'
@@ -46,6 +46,7 @@ gem 'will_paginate'
 gem 'rack-attack'
 gem 'rack-cors', require: 'rack/cors'
 gem 'sidekiq'
+gem 'sidekiq-unique-jobs'
 gem 'rails-settings-cached'
 gem 'simple-navigation'
 gem 'statsd-instrument'

Gemfile.lock

@@ -387,6 +387,9 @@ GEM
       connection_pool (~> 2.2, >= 2.2.0)
       rack-protection (>= 1.5.0)
       redis (~> 3.2, >= 3.2.1)
+    sidekiq-unique-jobs (4.0.18)
+      sidekiq (>= 2.6)
+      thor
     simple-navigation (4.0.3)
       activesupport (>= 2.3.2)
     simple_form (3.2.1)
@@ -510,6 +513,7 @@ DEPENDENCIES
   sass-rails (~> 5.0)
   sdoc (~> 0.4.0)
   sidekiq
+  sidekiq-unique-jobs
   simple-navigation
   simple_form
   simplecov

ISSUE_TEMPLATE.md

@@ -0,0 +1,5 @@
+[Issue text goes here].
+
+* * * *
+
+- [ ] I searched or browsed the repo’s other issues to ensure this is not a duplicate.

app/controllers/api/v1/apps_controller.rb

@@ -4,6 +4,12 @@ class Api::V1::AppsController < ApiController
   respond_to :json
 
   def create
-    @app = Doorkeeper::Application.create!(name: params[:client_name], redirect_uri: params[:redirect_uris], scopes: (params[:scopes] || Doorkeeper.configuration.default_scopes), website: params[:website])
+    @app = Doorkeeper::Application.create!(name: app_params[:client_name], redirect_uri: app_params[:redirect_uris], scopes: (app_params[:scopes] || Doorkeeper.configuration.default_scopes), website: app_params[:website])
+  end
+
+  private
+
+  def app_params
+    params.permit(:client_name, :redirect_uris, :scopes, :website)
   end
 end

app/controllers/api/v1/follows_controller.rb

@@ -7,7 +7,7 @@ class Api::V1::FollowsController < ApiController
   respond_to :json
 
   def create
-    raise ActiveRecord::RecordNotFound if params[:uri].blank?
+    raise ActiveRecord::RecordNotFound if follow_params[:uri].blank?
 
     @account = FollowService.new.call(current_user.account, target_uri).try(:target_account)
     render action: :show
@@ -16,6 +16,10 @@ class Api::V1::FollowsController < ApiController
   private
 
   def target_uri
-    params[:uri].strip.gsub(/\A@/, '')
+    follow_params[:uri].strip.gsub(/\A@/, '')
+  end
+
+  def follow_params
+    params.permit(:uri)
   end
 end

app/controllers/api/v1/media_controller.rb

@@ -10,10 +10,16 @@ class Api::V1::MediaController < ApiController
   respond_to :json
 
   def create
-    @media = MediaAttachment.create!(account: current_user.account, file: params[:file])
+    @media = MediaAttachment.create!(account: current_user.account, file: media_params[:file])
   rescue Paperclip::Errors::NotIdentifiedByImageMagickError
     render json: { error: 'File type of uploaded media could not be verified' }, status: 422
   rescue Paperclip::Error
     render json: { error: 'Error processing thumbnail for uploaded media' }, status: 500
   end
+
+  private
+
+  def media_params
+    params.permit(:file)
+  end
 end

app/controllers/api/v1/reports_controller.rb

@@ -12,13 +12,19 @@ class Api::V1::ReportsController < ApiController
   end
 
   def create
-    status_ids = params[:status_ids].is_a?(Enumerable) ? params[:status_ids] : [params[:status_ids]]
+    status_ids = report_params[:status_ids].is_a?(Enumerable) ? report_params[:status_ids] : [report_params[:status_ids]]
 
     @report = Report.create!(account: current_account,
-                             target_account: Account.find(params[:account_id]),
+                             target_account: Account.find(report_params[:account_id]),
                              status_ids: Status.find(status_ids).pluck(:id),
-                             comment: params[:comment])
+                             comment: report_params[:comment])
 
     render :show
   end
+
+  private
+
+  def report_params
+    params.permit(:account_id, :comment, status_ids: [])
+  end
 end

app/controllers/api/v1/statuses_controller.rb

@@ -62,10 +62,10 @@ class Api::V1::StatusesController < ApiController
   end
 
   def create
-    @status = PostStatusService.new.call(current_user.account, params[:status], params[:in_reply_to_id].blank? ? nil : Status.find(params[:in_reply_to_id]), media_ids: params[:media_ids],
+    @status = PostStatusService.new.call(current_user.account, status_params[:status], status_params[:in_reply_to_id].blank? ? nil : Status.find(status_params[:in_reply_to_id]), media_ids: status_params[:media_ids],
-                                                                                                                                                             sensitive: params[:sensitive],
+                                                                                                                                                                                  sensitive: status_params[:sensitive],
-                                                                                                                                                             spoiler_text: params[:spoiler_text],
+                                                                                                                                                                                  spoiler_text: status_params[:spoiler_text],
-                                                                                                                                                             visibility: params[:visibility],
+                                                                                                                                                                                  visibility: status_params[:visibility],
                                                                                                                                                                                   application: doorkeeper_token.application)
     render action: :show
   end
@@ -111,4 +111,8 @@ class Api::V1::StatusesController < ApiController
     @status = Status.find(params[:id])
     raise ActiveRecord::RecordNotFound unless @status.permitted?(current_account)
   end
+
+  def status_params
+    params.permit(:status, :in_reply_to_id, :sensitive, :spoiler_text, :visibility, media_ids: [])
+  end
 end

app/controllers/application_controller.rb

@@ -39,7 +39,14 @@ class ApplicationController < ActionController::Base
   end
 
   def set_user_activity
-    current_user.touch(:current_sign_in_at) if !current_user.nil? && (current_user.current_sign_in_at.nil? || current_user.current_sign_in_at < 24.hours.ago)
+    return unless !current_user.nil? && (current_user.current_sign_in_at.nil? || current_user.current_sign_in_at < 24.hours.ago)
+
+    # Mark user as signed-in today
+    current_user.update_tracked_fields(request)
+
+    # If the sign in is after a two week break, we need to regenerate their feed
+    RegenerationWorker.perform_async(current_user.account_id) if current_user.last_sign_in_at < 14.days.ago
+    return
   end
 
   def check_suspension

app/controllers/oauth/authorizations_controller.rb

@@ -3,6 +3,7 @@
 class Oauth::AuthorizationsController < Doorkeeper::AuthorizationsController
   skip_before_action :authenticate_resource_owner!
 
+  before_action :set_locale
   before_action :store_current_location
   before_action :authenticate_resource_owner!
 
@@ -11,4 +12,10 @@ class Oauth::AuthorizationsController < Doorkeeper::AuthorizationsController
   def store_current_location
     store_location_for(:user, request.url)
   end
+
+  def set_locale
+    I18n.locale = current_user.try(:locale) || I18n.default_locale
+  rescue I18n::InvalidLocale
+    I18n.locale = I18n.default_locale
+  end
 end

app/lib/feed_manager.rb

@@ -5,7 +5,7 @@ require 'singleton'
 class FeedManager
   include Singleton
 
-  MAX_ITEMS = 800
+  MAX_ITEMS = 400
 
   def key(type, id)
     "feed:#{type}:#{id}"
@@ -50,42 +50,39 @@ class FeedManager
 
   def merge_into_timeline(from_account, into_account)
     timeline_key = key(:home, into_account.id)
+    query        = from_account.statuses.limit(FeedManager::MAX_ITEMS / 4)
 
-    from_account.statuses.limit(MAX_ITEMS).each do |status|
+    if redis.zcard(timeline_key) >= FeedManager::MAX_ITEMS / 4
+      oldest_home_score = redis.zrange(timeline_key, 0, 0, with_scores: true)&.first&.last&.to_i || 0
+      query = query.where('id > ?', oldest_home_score)
+    end
+
+    redis.pipelined do
+      query.each do |status|
         next if status.direct_visibility? || filter?(:home, status, into_account)
         redis.zadd(timeline_key, status.id, status.id)
       end
+    end
 
     trim(:home, into_account.id)
   end
 
   def unmerge_from_timeline(from_account, into_account)
     timeline_key = key(:home, into_account.id)
+    oldest_home_score = redis.zrange(timeline_key, 0, 0, with_scores: true)&.first&.last&.to_i || 0
 
-    from_account.statuses.select('id').find_each do |status|
+    from_account.statuses.select('id').where('id > ?', oldest_home_score).find_in_batches do |statuses|
+      redis.pipelined do
+        statuses.each do |status|
           redis.zrem(timeline_key, status.id)
           redis.zremrangebyscore(timeline_key, status.id, status.id)
         end
       end
+    end
+  end
 
   def inline_render(target_account, template, object)
-    rabl_scope = Class.new do
+    Rabl::Renderer.new(template, object, view_path: 'app/views', format: :json, scope: InlineRablScope.new(target_account)).render
-      include RoutingHelper
-
-      def initialize(account)
-        @account = account
-      end
-
-      def current_user
-        @account.try(:user)
-      end
-
-      def current_account
-        @account
-      end
-    end
-
-    Rabl::Renderer.new(template, object, view_path: 'app/views', format: :json, scope: rabl_scope.new(target_account)).render
   end
 
   private
@@ -95,36 +92,38 @@ class FeedManager
   end
 
   def filter_from_home?(status, receiver)
-    return true if receiver.muting?(status.account)
+    return true if status.reply? && status.in_reply_to_id.nil?
 
-    should_filter = false
+    check_for_mutes = [status.account_id]
+    check_for_mutes.concat([status.reblog.account_id]) if status.reblog?
 
-    if status.reply? && status.in_reply_to_id.nil?
+    return true if receiver.muting?(check_for_mutes)
-      should_filter = true
+
-    elsif status.reply? && !status.in_reply_to_account_id.nil?                # Filter out if it's a reply
+    check_for_blocks = status.mentions.map(&:account_id)
+    check_for_blocks.concat([status.reblog.account_id]) if status.reblog?
+
+    return true if receiver.blocking?(check_for_blocks)
+
+    if status.reply? && !status.in_reply_to_account_id.nil?                   # Filter out if it's a reply
       should_filter   = !receiver.following?(status.in_reply_to_account)      # and I'm not following the person it's a reply to
       should_filter &&= !(receiver.id == status.in_reply_to_account_id)       # and it's not a reply to me
       should_filter &&= !(status.account_id == status.in_reply_to_account_id) # and it's not a self-reply
+      return should_filter
     elsif status.reblog?                                                      # Filter out a reblog
-      should_filter = receiver.blocking?(status.reblog.account)               # if I'm blocking the reblogged person
+      return status.reblog.account.blocking?(receiver)                        # or if the author of the reblogged status is blocking me
-      should_filter ||= receiver.muting?(status.reblog.account)               # or muting that person
-      should_filter ||= status.reblog.account.blocking?(receiver)             # or if the author of the reblogged status is blocking me
     end
 
-    should_filter ||= receiver.blocking?(status.mentions.map(&:account_id))   # or if it mentions someone I blocked
+    false
-
-    should_filter
   end
 
   def filter_from_mentions?(status, receiver)
-    should_filter   = receiver.id == status.account_id                                      # Filter if I'm mentioning myself
+    check_for_blocks = [status.account_id]
-    should_filter ||= receiver.blocking?(status.account)                                    # or it's from someone I blocked
+    check_for_blocks.concat(status.mentions.select('account_id').map(&:account_id))
-    should_filter ||= receiver.blocking?(status.mentions.includes(:account).map(&:account)) # or if it mentions someone I blocked
+    check_for_blocks.concat([status.in_reply_to_account]) if status.reply? && !status.in_reply_to_account_id.nil?
-    should_filter ||= (status.account.silenced? && !receiver.following?(status.account))    # of if the account is silenced and I'm not following them
 
-    if status.reply? && !status.in_reply_to_account_id.nil?                                 # or it's a reply
+    should_filter   = receiver.id == status.account_id                                      # Filter if I'm mentioning myself
-      should_filter ||= receiver.blocking?(status.in_reply_to_account)                      # to a user I blocked
+    should_filter ||= receiver.blocking?(check_for_blocks)                                  # or it's from someone I blocked, in reply to someone I blocked, or mentioning someone I blocked
-    end
+    should_filter ||= (status.account.silenced? && !receiver.following?(status.account))    # of if the account is silenced and I'm not following them
 
     should_filter
   end

app/lib/inline_rabl_scope.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class InlineRablScope
+  include RoutingHelper
+
+  def initialize(account)
+    @account = account
+  end
+
+  def current_user
+    @account.try(:user)
+  end
+
+  def current_account
+    @account
+  end
+end

app/models/feed.rb

@@ -10,17 +10,9 @@ class Feed
     max_id     = '+inf' if max_id.blank?
     since_id   = '-inf' if since_id.blank?
     unhydrated = redis.zrevrangebyscore(key, "(#{max_id}", "(#{since_id}", limit: [0, limit], with_scores: true).map(&:last).map(&:to_i)
-
-    # If we're after most recent items and none are there, we need to precompute the feed
-    if unhydrated.empty? && max_id == '+inf' && since_id == '-inf'
-      RegenerationWorker.perform_async(@account.id, @type)
-      @statuses = Status.send("as_#{@type}_timeline", @account).cache_ids.paginate_by_max_id(limit, nil, nil)
-    else
     status_map = Status.where(id: unhydrated).cache_ids.map { |s| [s.id, s] }.to_h
-      @statuses  = unhydrated.map { |id| status_map[id] }.compact
-    end
 
-    @statuses
+    unhydrated.map { |id| status_map[id] }.compact
   end
 
   private

app/models/status.rb

@@ -188,7 +188,7 @@ class Status < ApplicationRecord
   end
 
   before_validation do
-    text.strip!
+    text&.strip!
     spoiler_text&.strip!
 
     self.reply                  = !(in_reply_to_id.nil? && thread.nil?) unless reply

app/services/precompute_feed_service.rb

@@ -5,11 +5,13 @@ class PrecomputeFeedService < BaseService
   # @param [Symbol] type :home or :mentions
   # @param [Account] account
   def call(_, account)
-    Status.as_home_timeline(account).limit(FeedManager::MAX_ITEMS).each do |status|
+    redis.pipelined do
+      Status.as_home_timeline(account).limit(FeedManager::MAX_ITEMS / 4).each do |status|
         next if status.direct_visibility? || FeedManager.instance.filter?(:home, status, account)
         redis.zadd(FeedManager.instance.key(:home, account.id), status.id, status.reblog? ? status.reblog_of_id : status.id)
       end
     end
+  end
 
   private
 

app/workers/after_remote_follow_request_worker.rb

@@ -3,7 +3,7 @@
 class AfterRemoteFollowRequestWorker
   include Sidekiq::Worker
 
-  sidekiq_options retry: 5
+  sidekiq_options queue: 'pull', retry: 5
 
   def perform(follow_request_id)
     follow_request  = FollowRequest.find(follow_request_id)

app/workers/after_remote_follow_worker.rb

@@ -3,7 +3,7 @@
 class AfterRemoteFollowWorker
   include Sidekiq::Worker
 
-  sidekiq_options retry: 5
+  sidekiq_options queue: 'pull', retry: 5
 
   def perform(follow_id)
     follow          = Follow.find(follow_id)

app/workers/import_worker.rb

@@ -5,7 +5,7 @@ require 'csv'
 class ImportWorker
   include Sidekiq::Worker
 
-  sidekiq_options retry: false
+  sidekiq_options queue: 'pull', retry: false
 
   def perform(import_id)
     import = Import.find(import_id)

app/workers/link_crawl_worker.rb

@@ -3,7 +3,7 @@
 class LinkCrawlWorker
   include Sidekiq::Worker
 
-  sidekiq_options retry: false
+  sidekiq_options queue: 'pull', retry: false
 
   def perform(status_id)
     FetchLinkCardService.new.call(Status.find(status_id))

app/workers/merge_worker.rb

@@ -3,6 +3,8 @@
 class MergeWorker
   include Sidekiq::Worker
 
+  sidekiq_options queue: 'pull'
+
   def perform(from_account_id, into_account_id)
     FeedManager.instance.merge_into_timeline(Account.find(from_account_id), Account.find(into_account_id))
   end

app/workers/notification_worker.rb

@@ -3,7 +3,7 @@
 class NotificationWorker
   include Sidekiq::Worker
 
-  sidekiq_options retry: 5
+  sidekiq_options queue: 'push', retry: 5
 
   def perform(xml, source_account_id, target_account_id)
     SendInteractionService.new.call(xml, Account.find(source_account_id), Account.find(target_account_id))

app/workers/regeneration_worker.rb

@@ -3,7 +3,9 @@
 class RegenerationWorker
   include Sidekiq::Worker
 
-  def perform(account_id, timeline_type)
+  sidekiq_options queue: 'pull', backtrace: true, unique: :until_executed
-    PrecomputeFeedService.new.call(timeline_type, Account.find(account_id))
+
+  def perform(account_id, _ = :home)
+    PrecomputeFeedService.new.call(:home, Account.find(account_id))
   end
 end

app/workers/thread_resolve_worker.rb

@@ -3,7 +3,7 @@
 class ThreadResolveWorker
   include Sidekiq::Worker
 
-  sidekiq_options retry: false
+  sidekiq_options queue: 'pull', retry: false
 
   def perform(child_status_id, parent_url)
     child_status  = Status.find(child_status_id)

app/workers/unmerge_worker.rb

@@ -3,6 +3,8 @@
 class UnmergeWorker
   include Sidekiq::Worker
 
+  sidekiq_options queue: 'pull'
+
   def perform(from_account_id, into_account_id)
     FeedManager.instance.unmerge_from_timeline(Account.find(from_account_id), Account.find(into_account_id))
   end

docker-compose.yml

@@ -33,7 +33,7 @@ services:
     restart: always
     build: .
     env_file: .env.production
-    command: bundle exec sidekiq -q default -q mailers -q push
+    command: bundle exec sidekiq -q default -q mailers -q pull -q push
     depends_on:
       - db
       - redis

docs/Running-Mastodon/Heroku-guide.md

@@ -8,6 +8,6 @@ Mastodon can theoretically run indefinitely on a free [Heroku](https://heroku.co
 1. Click the above button.
 2. Fill in the options requested.
   * You can use a .herokuapp.com domain, which will be simple to set up, or you can use a custom domain. If you want a custom domain and HTTPS, you will need to upgrade to a paid plan (to use Heroku's SSL features), or set up [CloudFlare](https://cloudflare.com) who offer free "Flexible SSL" (note: CloudFlare have some undefined limits on WebSockets. So far, no one has reported hitting concurrent connection limits).
-  * You will want Amazon S3 for file storage. The only exception is for development purposes, where you may not care if files are not saaved. Follow a guide online for creating a free Amazon S3 bucket and Access Key, then enter the details.
+  * You will want Amazon S3 for file storage. The only exception is for development purposes, where you may not care if files are not saved. Follow a guide online for creating a free Amazon S3 bucket and Access Key, then enter the details.
   * If you want your Mastodon to be able to send emails, configure SMTP settings here (or later). Consider using [Mailgun](https://mailgun.com) or similar, who offer free plans that should suit your interests.
 3. Deploy! The app should be set up, with a working web interface and database. You can change settings and manage versions from the Heroku dashboard.

docs/Running-Mastodon/Production-guide.md

@@ -180,7 +180,7 @@ User=mastodon
 WorkingDirectory=/home/mastodon/live
 Environment="RAILS_ENV=production"
 Environment="DB_POOL=5"
-ExecStart=/home/mastodon/.rbenv/shims/bundle exec sidekiq -c 5 -q default -q mailers -q push
+ExecStart=/home/mastodon/.rbenv/shims/bundle exec sidekiq -c 5 -q default -q mailers -q pull -q push
 TimeoutSec=15
 Restart=always
 

docs/Using-Mastodon/List-of-Mastodon-instances.md

@@ -11,17 +11,31 @@ There is also a list at [instances.mastodon.xyz](https://instances.mastodon.xyz)
 | [animalliberation.social](https://animalliberation.social) |Animal Rights|Yes|No|
 | [socially.constructed.space](https://socially.constructed.space) |Single user|No|No|
 | [epiktistes.com](https://epiktistes.com) |N/A|Yes|No|
+| [fern.surgeplay.com](https://fern.surgeplay.com) |Federates everywhere, Minecraft-focused|Yes|No
 | [gay.crime.team](https://gay.crime.team) |the place for doin' gay crime online (please don't actually do crime here)|Yes|No|
 | [icosahedron.website](https://icosahedron.website/) |Icosahedron-themed (well, visually), open registration.|Yes|No|
 | [memetastic.space](https://memetastic.space) |Memes|Yes|No|
 | [social.diskseven.com](https://social.diskseven.com) |Single user|No|No (DNS entry but no response)|
 | [social.gestaltzerfall.net](https://social.gestaltzerfall.net) |Single user|No|No|
 | [mastodon.xyz](https://mastodon.xyz) |N/A|Yes|Yes|
-| [social.targaryen.house](https://social.targaryen.house) |N/A|Yes|No|
+| [social.targaryen.house](https://social.targaryen.house) |Federates everywhere, quick updates.|Yes|Yes|
 | [social.mashek.net](https://social.mashek.net) |Themed and customised for Mashekstein Labs community. Selectively federates.|Yes|No|
 | [masto.themimitoof.fr](https://masto.themimitoof.fr) |N/A|Yes|Yes|
 | [social.imirhil.fr](https://social.imirhil.fr) |N/A|No|Yes|
 | [social.wxcafe.net](https://social.wxcafe.net) |Open registrations, federates everywhere, no moderation yet|Yes|Yes|
 | [octodon.social](https://octodon.social) |Open registrations, federates everywhere, cutest instance yet|Yes|Yes|
+| [hostux.social](https://hostux.social) |N/A|Yes|Yes|
+| [social.alex73630.xyz](https://social.alex73630.xyz) |Francophones|Yes|Yes|
+| [maly.io](https://maly.io) |N/A|Yes|No|
+| [social.lou.lt](https://social.lou.lt) |N/A|Yes|No|
+| [mastodon.ninetailed.uk](https://mastodon.ninetailed.uk) |N/A|Yes|No|
+| [soc.louiz.org](https://soc.louiz.org) |"Coucou"|Yes|No|
+| [7nw.eu](https://7nw.eu) |N/A|Yes|No|
+| [mastodon.gougere.fr](https://mastodon.gougere.fr)|N/A|Yes|No|
+| [aleph.land](https://aleph.land)|N/A|Yes|No|
+| [share.elouworld.org](https://share.elouworld.org)|N/A|No|No|
+| [social.lkw.tf](https://social.lkw.tf)|N/A|No|No|
+| [manowar.social](https://manowar.social)|N/A|No|No|
+| [social.ballpointcarrot.net](https://social.ballpointcarrot.net)|Down at time of entry|No|No|
 
 Let me know if you start running one so I can add it to the list! (Alternatively, add it yourself as a pull request).

docs/Using-Mastodon/User-guide.md

@@ -26,17 +26,17 @@ Mastodon User's Guide
 
 ## Intro
 
-Mastodon is a social network application based on the GNU Social protocol. It behaves a lot like other social networks, especially Twitter, with one key difference - it is open-source and anyone can start their own server (also called an "instance"), and users of any instance can interact freely with those of other instances (called "federation"). Thus, it is possible for small communities to set up their own servers to use amongst themselves while also allowing interaction with other communities.
+Mastodon is a social network application based on the GNU Social protocol. It behaves a lot like other social networks, especially Twitter, with one key difference - it is open-source and anyone can start their own server (also called an "*instance*"), and users of any instance can interact freely with those of other instances (called "*federation*"). Thus, it is possible for small communities to set up their own servers to use amongst themselves while also allowing interaction with other communities.
 
 #### Decentralization and Federation
 
-Mastodon is a system decentralized through a concept called "federation" - rather than depending on a single person or organization to run its infrastructure, anyone can download and run the software and run their own server. Federation means different Mastodon servers can interact with each other seamlessly, similar to e.g. e-mail.
+Mastodon is a system decentralized through a concept called "*federation*" - rather than depending on a single person or organization to run its infrastructure, anyone can download and run the software and run their own server. Federation means different Mastodon servers can interact with each other seamlessly, similar to e.g. e-mail.
 
 As such, anyone can download Mastodon and e.g. run it for a small community of people, but any user registered on that instance can follow and send and read posts from other Mastodon instances (as well as servers running other GNU Social-compatible services). This means that not only is users' data not inherently owned by a company with an interest in selling it to advertisers, but also that if any given server shuts down its users can set up a new one or migrate to another instance, rather than the entire service being lost.
 
 Within each Mastodon instance, usernames just appear as `@username`, similar to other services such as Twitter. Users from other instances appear, and can be searched for and followed, as `@user@servername.ext` - so e.g. `@gargron` on the `mastodon.social` instance can be followed from other instances as `@gargron@mastodon.social`).
 
-Posts from users on external instances are "federated" into the local one, i.e. if `user1@mastodon1` follows `user2@gnusocial2`, any posts `user2@gnusocial2` makes appear in both `user1@mastodon`'s Home feed and the public timeline on the `mastodon1` server. Mastodon server administrators have some control over this and can exclude users' posts from appearing on the public timeline; post privacy settings from users on Mastodon instances also affect this, see below in the [Toot Privacy](User-guide.md#toot-privacy) section.
+Posts from users on external instances are "*federated*" into the local one, i.e. if `user1@mastodon1` follows `user2@gnusocial2`, any posts `user2@gnusocial2` makes appear in both `user1@mastodon`'s Home feed and the public timeline on the `mastodon1` server. Mastodon server administrators have some control over this and can exclude users' posts from appearing on the public timeline; post privacy settings from users on Mastodon instances also affect this, see below in the [Toot Privacy](User-guide.md#toot-privacy) section.
 
 ## Getting Started