TwitVim

TwitVim is a Twitter client implemented as a Vim plugin.

TwitVim supports many features of typical Twitter clients, including:

Friends, User, Direct Message, Mentions, and List timelines
Hashtags and Twitter Search
Posting updates, replying, and retweeting
List management
In-reply-to
User profile display
URL shortening and expansion, including auto-expansion of t.co URLs
OAuth login and fast switching between multiple users
Timeline filtering

TwitVim also supports identi.ca through its Twitter-compatible API.