There are approximately 2 billion monthly users on Facebook; how many do you know?

For most of us, there are a few hundred people in our friends list and by now we've all added nearly everyone we know or even knew.

So why accept any friend requests from people we don't know?

It's one of the most dangerous things you can do on Facebook. Strangers as friends is simply not a good idea for several reasons.

First, everything you post, upload or comment on is viewable by all of your friends (unless you choose to post to only some friends).

Do you really want a stranger to see your posts from vacation that show you're out of town? Do you really want someone you don't know to see pictures of your children and know where they go to school? Is there any reason it would be a good idea for a total stranger to see your phone number, email address, physical home address, where you work and where you went to school?

All of those things are likely somewhere to be found on your Facebook account.

If that information falls into the wrong hands a hacker would have virtually everything they need to steal your identity.

Also consider how someone might be able to find out answers to security questions used to re-set passwords on other accounts.

A common security question is "what's your mother's maiden name?" If a hacker has access to your Facebook account they could likely find out who your mother is (if she's included among your family information) and like many women on Facebook, they include their maiden name.

Another reason you should never accept a friend request from someone you don't know is you don't know if the request is coming from a real person.

Hackers do set up Facebook accounts for fake people using photos they find from somewhere on the internet.

I got a friend request some time ago from a woman I did not know. Her profile picture was of a very attractive young woman.

When I checked her profile page I saw we had seven mutual friends. By using a reverse-image search I saw that her profile pic was of a model that was available from a library of royalty free photos.

If you accept a friend request from a fake profile set up by a hacker, they can not only see everything you upload to Facebook they can download your photos and information and set up a fake account using your name and sending requests out to all of your friends.

Once that happens, their method of operation can gather dozens or hundreds of accounts which allows them to send those new 'friends' spam and links to malware.

When you get a friend request from someone who's account was hacked, this is likely how it happens.

So never ever ever accept a friend request from a stranger. Ever.