I’ll admit to some amusement when mature adult Facebook friends "like" pages such as "[SHOCKING] At 15, she did THAT in public school EVERY day". Usually these pages are accompanied by images of young girls in suggestive poses. Of course when confronted about their salacious ways they’ll always swear black and blue that they never “liked” the link. Except they did, they just didn't know it. What we're talking about here is a Facebook “worm” or in other words a script which replicates itself. Someone sees it, clicks the link then it automatically appears on their wall without their knowledge. Three of their friends then see it on their wall and click through then three of their friends do the same and so on and so forth. But how can this happen? Why does Facebook allow someone to inadvertently “like” a page they would never actually intentionally like, or at least not intentionally broadcast that they like it! It’s actually both very simple and quite clever so let’s pull it apart and figure out how this is working.