By default, Ubuntu ships Gwibber, a user-friendly powerful social client that incorporates an effective set of social services, like Twitter, Identi.ca, etc, allowing users to simultaneously enjoy multiple online services (like for instance, displaying messages from both Twitter and Identi.ca under the same window).
Yet, it seems that various users, while enjoying Gwibber and its multiple-supported services, seem to perceive Gwibber as slow, requesting various optimizations and performance improvements.