In This Chapter
If you're familiar with Apple's iPhone commercials, you've probably heard the phrase, “There's an app for that.” In iPhone-land, an app is a kind of program you add to your phone that suits your particular needs. It might help you track what you eat, or it might be a game you can play alone or with friends. iPhone apps take something that is already useful (your phone) and make it even more useful and fun.
Similarly, apps on Facebook take something that is already useful (Facebook) and make it even more useful and fun. They can take advantage (with your permission) of some of the parts of Facebook that are hard to replicate elsewhere, things like your Friend List, the things you like, and News Feed.
On Facebook, apps can exist for a whole host of reasons. They may be related to sharing things like what you're reading or listening to. They can be games you can play with your friends — both on Facebook and on your mobile phone. And they are actually found on other websites, because you can use your Facebook information, like your name and profile picture, to skip over setting up multiple profiles on multiple sites.
For a long time, Facebook was the only company that could build apps for Facebook. And it did; it built Photos, ...