Twiffid - what an awesome idea…“this site automatically detects the feeds of the websites your Twitter friends have listed in their Twitter profiles and presents them to you in a Twitter-like format”…this could make a great RSS Reader alternative…streams are so in vogue.
TwitterFresh - an alternate website for Twitter, this one auto-refreshes your friends timeline every three minutes
Twitter StreamGraphs - a graph from the latest 200 tweets which contain a search word or user ID, if you hover over parts of the graph it will change colour, if you then click it will generate a new graph for that keyword…also see Tweet Clouds.
Here’s my Twitter StreamGraph.
Easy Tweets - Like Matt you can manage multiple Twitter accounts, and like Tweet Later and others you can schedule Tweets for future posting, and like Twitterfeed you can re-syndicate posts from RSS feeds into your stream.