There's more to your online spring cleaning than deciding how far to go in limiting access to your Facebook profile. Other advisable precautions:
Google yourself. Or use any other search engine of your choice to find everything that's out there about you for people to see.
Not your best feature showing? Erase what you control and see if you can get others to take down what they control -- that party photo on your roommate's blog, for instance.
Bury your dirt. If you can't make some bad things go away, about your only option is to rig future searches so that your favorite "hits" come up first and the rest don't show up until several screens later. This requires some technical know-how.
Don't bring it up. You might be inclined to pre-emptively mention any of your unflattering online presences in a job interview, but restrain yourself. If you've made it this far, the interviewer probably checked you out online already, and either missed them or wasn't put off.
You might get lucky. Many employers understand college is a time of experimentation and cut students some slack. But try to get some signs of maturity online -- a résumé showing volunteer work, for example -- before too many more years pass.
More help. Go to the Electronic Frontier Foundation's website: www.eff.org. Under "Topics," click on "Bloggers' Rights."
Sources: Macalester College; Electronic Frontier Foundation