MacOS – Facebook and Twitter sharing is missing in Notification Center

The Facebook integration wasn't available when this question was asked - it was added in OS X 10.8.2 in September 2012.

To activate Twitter and Facebook sharing, you must first configure at least one Twitter and / or Facebook account via System Preferences -> Mail, Contacts & Calendars -> Add Account -> Twitter (or Facebook). Once you've successfully added a Twitter account, the Twitter widget should appear at the top of Notification Center.

You can get the home timeline from the Twitter API and display tweets using terminal-notifier.

#!/usr/bin/env ruby -KU -rubygems

require 'twitter'
require 'cgi'

Twitter.configure do |config|
  config.consumer_key = ""
  config.consumer_secret = ""
  config.oauth_token = ""
  config.oauth_token_secret = ""
end

timeline = Twitter.home_timeline
first = timeline.first.id
previous = `defaults read me.lri.scripts nctwitter 2> /dev/null`.chomp
minid = previous == "" ? 0 : previous.to_i + 1
`defaults write me.lri.scripts nctwitter #{first}`

timeline.each do |tweet|
  break if tweet.id <= minid
  system("terminal-notifier", "-message", CGI.unescapeHTML(tweet.text),
  "-title", tweet.user.screen_name)
  # system("/usr/local/bin/growlnotify", "-t", tweet.user.screen_name,
  # "-m", CGI.unescapeHTML(tweet.text))
end

growlnotify would stack multiple notifications and not clip the text in long tweets.

The Twitter library can be installed with sudo gem install twitter.

You can run the script every minute by editing the crontab with EDITOR=nano crontab -e and adding a line like * * * * * ~/bin/nctwitter.

A recent update to Tweetbot added an option to send notifications for all tweets: