Let's stop these sharks!
This group was created to raise awareness in the TF2 community about sharks, individuals that target inexperienced players and attempt to scam them of valuable items. This can be done in a variety of ways, though a particularly popular method is using large amounts of relatively worthless items to obtain an unusual hat (or promos) from an unsuspecting user.
note: there are most likely similar groups on Steam, but I find it to be a pressing matter. Only good can come out of another such group.