Here we go again. I've seen this one doing the rounds before, but it's just come back...
YOUR PHONE NUMBER IS NOW ON FACEBOOK!! NO JOKE... Go to the top right of your screen, click Account then Edit Friends. Go to the left side of your screen and click Phonebook. Everyone's phone numbers are now being published.
Well, for a start, this is nothing new. Here's a revelation: If you put something on your Facebook profile, and allow your details to be viewed by your friends - guess what? They'll be able to see it. Amazing. (That's a bit like being surprised if people read your profile updates.)
If you visit a friend's profile, click on the Info tab and scroll down to Contact Information, you'll be able to see their phone number, email, website address etc. - if they have chosen to post it in the first place. This has been the case for simply ages. The Facebook 'phone book' is no more than a compilation of information that you already have.
Check your profile settings. (They default to Friends Only, as a rule.) Click Account>Privacy Settings. Have a look at Contact Information in that list. If (as seems reasonable) you want your Friends to be able to see this, but not Friends of Friends or the whole world, make sure that's the setting.
If you don't want anybody to see your phone number, not even a friend (in which case, what are they doing on your Friends list in the first place?) then take it off your Facebook profile entirely. (I'm assuming you don't need it there to remind yourself what it is.)
And please don't just repost these warnings without thinking about it. By and large, they are calculated to frighten and panic people. If they were calculated to inform, they'd be written in a far less inflammatory fashion. Next time you see something like this, please take a few minutes to check it out; find out the real story; and if you think there is something still in there that is worth knowing, edit it before you post it.
Oh, and this post - both on Facebook and here on my blog - is made available to Everyone. In case you were wondering.