The ability to remove one's self or to not be found is actually something that's fairly important online in general. I know that there are some states in Europe that have laws which allow citizens to demand that their data be removed from aggregators.
Crack provides a rudimentary and enjoyable break down on the subject:
http://www.cracked.com/article_18661...aking-out.html
If you're thinking about how exposed you are online remember, you don't need to make yourself invisible just hard enough that people will go after someone easier. It's that whole, 'outrunning your friend not the lion' thing.