Everybody has done it at some point, wrote their own name into Google and see if anything pops up. I just did it and had 619,000 hits. I had to wade through to page 6 before there was actually anything about the real me so the other 618,999 i presume are other people with the same name.
Luckily i haven't really got much of a footprint on the Internet but some people do put an amazing amount of personal details on this thing which has it advantages and disadvantages.
If i was an interviewer, i could plausibly google an applicant and there would be a good chance that they would have either a Facebook page, blog or somewhere where they spill their thoughts, likes and dislikes so i could form an opinion of them long before they get within the door for an interview.
Likewise, a boyfriend or girlfriend could be thoroughly checked out beforehand and a decision made to block their number in your mobile and leave a voicemail informing them that you are moving to Alaska.
My advice would be to be very careful with the information you put out there, even more so if you are actually a loon or have a liking for knitting your own underwear because the information is only a few clicks away and available to anyone who might have a motive for digging up facts about you.
Even worse you might google yourself and find out someone saying nasty things about you like this guy on page 10 of my google results who said I'm a real brick. That's not too bad, sturdy, reliable..my mistake, that first letter isn't a b. The bastard.