Facebook is the world’s popular way of communicating with each other, and this is the reason why we see lot of spammers spreading the malwares online and infecting the users.
After the nature’s attack on Japan recently, we are seeing lot of fake footage and video files in Facebook which asks users to click on the files and redirects to some other site having no video file. But in the process of doing this much, the user has unknowingly agreed to allow the app to use his info.
Consequence of this is that all the secret info of the user gets accessed by the malware. Not only this, user also gets a link posted to his wall that the link is liked by you (this is how the malware spreads).
In the time when people should come forward to help the humanity, spammers are actually trying to infect the users clicking on the unknown and fake links. To safeguard against this, you are advised to not to click on any link that you are not sure of, and never install anything asked by any site or link.