I picked up this great tip via Bob Garrett’s pointer to David Petherick’s The Next Web website .
If you are using Twitter’s browser UI, you can get the basic information on another user by typing whois UserName and clicking the Update button. You do need to be logged in to do this but you don’t need the typical ‘@’ symbol before the username.
Twitter will then display the basic information for that user!
Two related commands also available from Twitter’s Browser UI are:
If you decide to follow someone, you can type FOLLOW UserName.
If you want to stop following someone, you can type LEAVE UserName.