This is a
serious issue and
I hope you younger guys heed this warning.
As a principal, I've suspended and expelled students over their MySpace, Facebook and IM misbehavior. We have a company that does a web search on any faculty applicant which can lead to them not being offered a contract.
Colleges and universities have specialists who search the WWW (MySpace and Facebook in particular) before deciding upon offering students enrollment and expel students for web misbehavior.
My wife is the West Team Leader (everything west of the Mississippi River) for a Fortune Top 500 company, and she has had to fire employess and reject exceptionally qualified candidates for web-issues because the company does WWW searches on all potential hires and periodically on its employees.
And for anybody looking for employment with any organizatioin requiring an upper level
security clearance, this is an even GREATER issue.
REMEMBER -
the WWW is a public domain!
TS is 100% correct. 
Richard's $.02
