How do you come up with your online user names? For some people, it's probably an easy process. A couple of my friends use the same name for all of their communities, while others like to create new ones everywhere they go.
Right now, I have two Ravelry accounts. It was something of an accident, since I didn't learn that I could change my user name without creating a new account until after I created the second account. Oops! I'm going to ask the powers-that-be at Ravelry for help getting my accounts straightened out.