What does it mean when somebody is "following" you? I've got notifications that a couple of people are, and not being on social network sites or Twitter or like that, I don't know all of the lingo. Sounds creepy but maybe it isn't?
Just people who want to follow your activities (language progress, forum activity, etc.) and are notified of them them on their "stream". You might want to follow people yourself; people you find interesting to know what they are up to, like Luis, for instance, Duolingo's founder. He sometimes answers queries on the forum and reveals what cool new stuff they are or will be working on.