When deciding what sort of information you want to publish about yourself online, you almost need to treat yourself like a brand you are marketing. It is always worth a second thought about how a piece of information may impact peoples perceptions of you before you hit post. Remember that things on the Net can have a longer life than you intend. At the moment it is still easy to post things in a way that doesn’t link it directly to your name. It works for trolls, anonymity can work for you to.
There is an interesting article in The Independant that details some of the more tragic instances where information posted online has hurt the poster. While these are extreme examples, less drastic postings can still have an effect on you. It is common practice now for potential employers to google your name as part of the recruitment process, and that detail on your facebook page about the drunken antics over the weekend with your buddies might not cast you in the professional light you wish to project. I post here under my full name precisely so an employer who googles me will find my posts.
I posted a piece on Businessgeek last week about how I manage my information on social websites.