The latest scam to hit Facebook is trying to trick users into spreading spam with the offer of a "dislike" button, Graham Cluley, senior technology consultant at anti-virus firm Sophos, said in a blog post Monday. Many users have been clamoring for such a capability, as they could use the button to give a thumbs-down to posts, links or uploads of which they are not fond. A "like" button already exists. The scam entices users to click on a link and install a rogue Facebook application, Cluley said. If the app is given permission to run, it posts spam messages from the user's account and prompts them to complete an online survey that makes money for the perpetrators. — AM