Everybody keeps talking about it, but i can't figure what it is.
I would believe that it's a signature campaign (hehe), but where can i find it and how do i participate?
It's selling your signature to someone as ads.
Here you can see the available campaigns and which can accept you (rank Member) to join:
https://bitcointalk.org/index.php?topic=615953.0P.S.: I think you should move this to Service Discussion.