Twitter lets you send or receive messages up to 140 characters long. So, what’s so valuable about that?
Their length might make tweets seem a lot like text messages, but there’s a big difference: A text goes to the mobile phone of one person, while your tweet can reach a handful of people—or hundreds. Once you sign up, you choose who to follow, and how to pull the info you want from Twitter’s information stream. You can also push your own message out to all of your followers—and encourage them to check out your audiobook!
Follow the people you’d like to be associated with. Don't follow everyone who follows you. (This can become unmanageable, plus you might not want to indicate an interest in all of them).