I don’t know how many times I’ve seen a status come across my news feed that says “Facebook has an dislike button, install now!” Chances are now from what we’re being told by Sophos that these folks fell for a scam that really doesn’t truly add a dislike button anyway.
What’s installed is a Firefox add-on by FaceMod, but nobody will see your dislikes unless they got the add-on installed as well. Sophos says that the company is not involved with the scam, but is rather being used as bait.
Whoever’s behind it has rigged the Facebook app (which doesn’t install the add-on anyway) to silently update your Facebook status which in turn spreads it to your friends. In order to even gain access to the add-on, the user needs to fill out an online survey.
The survey seems to be how the scammers are making money through this scheme. Sophos recommends that users download FaceMod’s dislike button directly if they really want it, and ignore those status messages.