I read an article about this the other day. What is scary is the amount of information which pops up, especially if the subject uses a social networking site like facebook or myspace. It can literally tell you where someone lives, their phone number, relationship history, recent photos etc.
That would only apply though to cases where the user has allowed their information to be shared though. I can see it being an issue though with people who are ignorant of what sharing too much information on the web can actually mean in the long run.