[Confused!] Need Advice

If you PM me, I'll e-mail the link, due to the nature of the material I hope it's understandable why I don't wish to put the link up here and now, but this is most worrisome, to me.

Today I was trying to find my friends Occupational Therapist's last name, because I wanted to find her address and mail her my new e-mail address. Well, I'm looking at something I never expected to find, and would like to know what's the best way too approach it..

You see I found this website where it has respective social security numbers on it,(maybe everyone should check it out if we can figure out a way to set it up)and I just put the first 5 digits of mine and lo and behold it came up with the whole number and someone else is using it!!!!

It' also shows the phone number, the credit cards along with the last 3 digits on the back of the card and the address the state is right, where I was born, and lived up until some 23 years ago.

Not that I think it would help, but maybe contact the Social Security office? If someone else is registered with the same number, they should know about it. And if it's done illegally (ie. identity theft?) then I would think that alerting them might be a good call? I really don't know. That's some scary stuff.

Good idea, all I can do is try. I looked a little further into the website today, is when I had some time to look at it, and it seems like they admit its fake identies, but they seem to have everyones Social, including my friends. We don't appreciate it having even just the numbers.
How I found it was typing in Google a telephone number and then it went to a web page, where I scrolled down and saw the numbers of some Social Securities, and then I clicked on it and put the first 7 digits (my number has some 0's in it and it came up that. Why have anyone's Social and then put a faked name next to it. It is scary.(not that they'd get much out of mine, I should've thought further, if I can't get credit then no one else would be able to either. But why are they there?