Windows Malware has spread through Facebook before, however now its Mac Malware spreading through Facebook. Now Mac Malware has really picked up over the past few weeks. First we had the big outbreak of a Mac Fake, then it got updates so it did not need an admin password, now its spreading on Facebook. Its been very active in the Mac Computer Security world recently.
The FakeAV only launches if you go to the site on a Apple Mac machine. Once again its a MacDefender slike FakeAV so try avoid clicking on suspicious looking links on your Facebook. Also if you own a Mac now would be a good time to go install some computer security software on. Yes it may be a Mac but it is not immune to malware, that has been proven a lot recently in the past few weeks.
If you have already clicked on the link do not buy the software it offers, it is a scam and should be avoided.