Earthquake - Terminal-based Twitter Client with Streaming API support. Only supports Ruby 1.9 and later.
Gwibber - Gwibber is an open source microblogging client for GNOME developed with Python and GTK.
Tui - Twitter client based on mobile.twitter.com in menu bar. Features:
Choqok - Choqok - KDE Micro-Blogging Client The name comes from an ancient Persian word, means Sparrow!
TweetDeck - TweetDeck is your personal browser for staying in touch with what’s happening now.
Cato Social Network - Become Cato. Post Meows, get Not So Anonymous Messages, connect with other Catos & grow your online social network.