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.
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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.