Here's a rule of thumb to keep in mind while surfing the Net: If it sounds too good to be true, it's a scam. For the past three years, the world’s largest online social network has been plagued with shady messages and deceptive ad posts that have exposed millions of Facebook users and their friends to spam. Previous scams have taken advantage of the earthquake in Haiti, while the newest ones lure you by offering a free sex video featuring a celebrity. We advise you keep your guard up and resist the temptation to click on anything that looks too awesome to not be national news. Odds are its malware. As Facebook handles the latest influx of porn spammers, take a look at 10 Facebook Scams to Watch Out For.