You use Google for everything else in your life, but if you are applying to college (or a job, for that matter) - you really should use it on yourself. Thanks to popular social media sites such as Facebook, MySpace, Twitter, etc., you don't need a private eye to snoop into the lives of private citizens. Recruiters in corporate America routinely use social-networking tools to screen prospective employees and a recent study reports that college admissions offices are following this trend as well. In today's information overload society, 'reputation management' is now a standard operating procedure for anyone who wants to advance in the professional world.
As a general rule, it's probably not the best idea to post compromising photos and personal information - ANYWHERE! Can anything truly positive come from chronicling those embarrassing (not to mention ill-advised) teenage party antics? If you don't want your parents to see it, you probably don't want to share it with professional screeners that can make/break your acceptance to your first-choice school. If you are preparing your college application, do yourself a favor and scrub your favorite social sites of anything remotely questionable. You may not be able to control what your friends post on their sites, but at the very least you can make sure only 'G-rated' stuff comes up in a search for your name.
Remember, just because you delete something - does not mean it's gone forever. The almighty oracle that is Google has a long memory. If you want Google to be your pal, keep those youthful indiscretions where they belong - locked away in that impenetrable vault inside your head!