Gwibber - Gwibber is an open source microblogging client for GNOME developed with Python and GTK.
eXo Platform - Digital workplace solution
TweetDeck - TweetDeck is your personal browser for staying in touch with what’s happening now.
Basecamp - A simple and elegant project management system.
Tweetbot - Sync your timeline across your iPhone, iPad, and Mac. Mute tweets by user, hashtag, tweet source, or keywords (including regex). 3rd Party support for image, video, read later, and timeline sync services.
Slack - A messaging app for teams who see through the Earth!