Helping people with computers... one answer at a time.
Facebook has very sophisticated methods of matching you up with people you might know. It may seem scary, but they aren't stealing anything from your computer.
I've subscribed to Facebook to see what it was all about, but used a pseudonym instead of my real name, which is permitted, as I understand it. And an alias of my email address being an unidentifiable number. I now receive emails from Facebook listing people I might know. About half the people listed, I do know and are in my address book on my computer. It can't be a coincidence that these people are listed. They would not recognize the pseudonym I use so how does Facebook know that I know these people?
In this excerpt from Answercast #30, I look at some of the methods Facebook uses to find associations between people, it's not really anything to worry about.
Facebook friend suggestions can seem really spooky.
I do know that they're not going to go out and grab your address book unless you explicitly give it to them. There are some ways I know that they request access to some of your accounts, sometimes, but as long as you don't do that, they won't access your information.
Facebook does some amazingly intelligent stuff to infer who you know by what you do on Facebook.
For example, let's say you have three friends: A, B, and C. I'll give them generic names.
On Facebook, you go out and you friend A and B.
A and B happen to both know C.
So, because you're friends with A and B, and because A and B both know C, it's possible that Facebook says, "You know what, if these two friends of yours know this person, maybe you do too. So I'll suggest them as a possible friend for you."
The more complex your friends network gets, the more inferences Facebook can make. In fact, the better job it can do of figuring out who your friends might be.
You haven't given it any additional information,
It hasn't stolen any additional information from you,
It hasn't even used (in your case) your real email address.
All it's done is taken a look at who you have friended on Facebook.
Now, I say, "Friended." It is my belief that Facebook is looking at more than just who you friend.
Particularly if you have the ability to see your friend's activity without actually friending them on Facebook, it is possible that Facebook could notice that. That could be, from Facebook's perspective, as good as being their friend.
In other words, Facebook might say:
You know what, you spend a lot of time looking at person A's stuff,
And you spend a lot of time looking at person B's stuff,
And they both know person C,
So, I'm thinking you might know person C as well.
And again if you have no friends, all you had to do was spend enough time looking at friend A's stuff and friend B's stuff and Facebook might be able to infer who your other friends might be.
Another approach is taking a look at what pages you like. For example, if you go to the Ask Leo! Fan Page, and like it, then all of a sudden that is a connection between you and all of the other fans of Ask Leo!
That by itself probably doesn't mean a lot. But if you then go off and become a fan of another page, say, "This is True" or "Ask Dave Taylor," or any of a number of other fan pages on Facebook, and a few of the other fans of Ask Leo! also happen to be fans of those other pages.
Facebook might start to think, "You know, you people all have a lot of common interests. Maybe you should get together; maybe you should know each other. In fact, maybe you do know each other, and I'll suggest them as possible friends."
So in general, people really get spooked sometimes by the friend suggestions that they see. They are spooked sometimes by how accurate they are.
In my opinion, there's no need to be spooked at all.
Facebook is actually taking information that you're giving it... and that
information is your activity on Facebook. It's using that information to try
and figure out who you might know; who you might like to know; who you might
share common interests with; and suggest them then as possible
Next from Answercast 30 – How can I save my BIOS settings before replacing the CMOS battery?