I joined a website called wordpress.com, which you may have heard of. I stumbled across Kristen Lamb's blog and was sucked in by snappy, funny, and informative writing.
She has a book called We Are Not Alone: The Writer's Guide To Social Media, that she promotes. A lot. Curious, I bought it for my Amazon Kindle.
Kristen writes, "your big goal should be to link your name with your content." The absolute only user name you should use is the name you desire to publish under.
This makes sense! If your name is Smitty Smith, you want people to Google Smitty Smith and find that name. Not all of the silly user names you go by like 'CloudLover14' and 'HotChick4U'. And yes, these names most likely exist.
She also talks about understanding and gathering content, free social media sites and how to get your name out there without spamming and annoying people. It is important to connect with people, not send them screaming into the other room.
Then she discusses the rules of social media, organizing, and creating groups (this is how you get people to get more people), and much more.
The book is worth checking out.