There are a number of messages working their way around social networking sites like facebook, here is an example:
“If some boy called email@example.com adds u don’t accept it because its a hacker!!
Tell everyone on your list because if somebody on your list adds them u get them on your list he’ll figure out Your ID computer address, so copy and paste this message to everyone even if u don’t care for them and fast cause if he hacks their email he hacks your mail too!!!”
Advice as ever is not to add people as a “friend” that you don’t know offline. That said messages like this should not just be forwarded, as with similar emails that are common place, its best to research them. These are normally Hoax or Spam messages.
This one is a hoax, see: http://www.sophos.com/security/hoaxes/facebook_hacker.html