I cannot be searched, I won't come up. I have one friend. The only reason I activated an account was because said friend refused to email and only ever speaks to people on Facebook.... I wanted him to see pics of my DS2 after he was born, and the stubborn sod said to put them there and he'd take a look.
Now, he sounds like a stubborn arse- he is- but he's my friend, so I obliged,.....
If you set really strong security settings, really, no one can find you. And just don't put personal information on there.
I think it's a dangerous thing, and just one more way for whatever governments and agencies to track everything we are all doing. Seriously, all it takes is one little nutjob to find one of those lost Inland Revenue disks, get your nat ins no., your bank details, then your personal details off Facebook, or MUMSNET!, or wherever, stick it all together, and then steal your life!!! (!) All very Conspiracy Theory I know, but makes you think.....
Oh, and don't get me started on Tesco Clubcards!!!! (!)