Twitter Cheat Sheet
http://www.lexisclick.com/blog/twitter-cheat-sheet/

This includes useful tips and explanations of the most popular terms and icons on Twitter. Statistics for Twitter are more difficult to track down but Twitter themselves state that they have millions of users worldwide – though how many of these are active accounts is questionable. Love it or hate it you shouldn’t be ignoring it! This has been added to the tools section of Research Resources Subject Tracer™ Information Blog.