Its not essential to give away a whole load of information about yourself to use Facebook, nor to use some of its applications.
I've got quite a few on my page and none of them have asked me for any information.
Its also a good rule that you shouldn't put anything on the internet that you dont want the whole world to know. Just in case.
I use Facebook because i've traveled all over the world and i've got friends that dont live anywhere near me and i dont want to stay up until 3am to call them.
For the first time in my life, i'm in touch with Everyone I want to be in touch with, all in the same place. So, for me, it has its uses and worked very well in tandem with Real Life 1.0.