Facebook offers three basic ways to build your audience: Invite friends, Share your page, and Employ paid Facebook advertising. These are in order of scalability. Inviting your few hundred friends is a nice start, but it’s only a start. Sharing extends your impact, allowing you to post about your page on your own timeline, a friend’s timeline, in a group you belong to, or in a private message.
Again, these techniques can get a community started, but they don’t scale—and you need to be judicious in what you share and with whom. Never spam your friends! With the initial alpha community established, now you want to build up a big audience of loyal fans. Communities do reach critical mass, where the “friends of fans” reach extends toward the million-plus mark.
At that point, all you need to do is post, and your community will grow, by hundreds of fans a day. Why? Every post you make, assuming it has the hallmarks of good, provocative, interactive content, will inspire a number of comments and “likes.” These comments and “likes” are broadcast across Facebook to all the friends of fans. The same occurs with Twitter posts that are enthusiastically retweeted.