Tweetvisor, created by Nelu Lazar and launched in January 2009, offers users an alternative interface to view and interact with Twitter.
The site aggregates messages from other users directed to you (replies and direct messages) in the sidebar, and offers search in the middle of the screen. Users can save searches and see when new results pop up for that query.
But the compelling feature is the ability to easily administer and switch between multiple Twitter accounts.
Currently supporting groups and tags for friends timeline as well, and inline video replies for explaining what can not be explained in just 140 characters and continue the conversation.