Have you seen the following post anywhere on facebook ??
(|FireFox Update| New Look Facebook 2013 > http://soo.gd/928534699)
The above link is a virus and can harm you badly. On clicking on the link it will ask you to enable something on your firefox, and then next time when you will log in into your facebook account, you will find that this virus has posted the same post on all the groups you belongs to in facebook, on all your friends walls etc.
Most probably we will be banned even for posting anything on your own wall, because this virus has already posted a lots of spams, so facebook will consider it as misusing the feature.