How can I get my users to spread the good word about my app to their friends?
If success on Facebook is all about getting your message spread around the social graph, then the News Feed is your primary target. Think of it as the play-by-play announcer in a giant game of tag: almost every action you take on Facebook generates an item that appears in the Mini-Feed on your Profile. If it just stopped there it would still be a useful message-spreading tool, but luckily for us, the fun has just begun! Those same items can also appear in your friends’ News Feeds on their home pages, announcing everything you’ve done to everyone who cares.
Facebook processes over a billion News stories per day, running them through a super-sophisticated algorithm that determines which tidbits about your friends will turn up in your Feed. The end result is that your app can publish one story about each user every 12 hours, all of which will appear in that user’s Mini-Feed and some of which will get broadcast out to their friends via the News Feed.
My News Feed (Figure 2-20) contains some subset of the stories that have been published about my friends, as determined by Facebook’s top-secret algorithm, likely created by a crack team of ninjas and Tibetan monks.
Figure 2-20. My News Feed (names blurred to protect the not-so-innocent)
As seen here, the Feed includes ...