One great way to add followers is to get people engaged so they'll send you a tweet back. There's no better way to get people to respond than to pose questions. Facebook quizzes have shown that people are willing to respond to even the silliest of public opinion polls. So throw some questions on your Twitter and see if you can get people talking. Ask what people's favorite TV show is or who should win American Idol. If there's a hot news item, poll your followers. For instance, in May 2009 the swine flu grabbed headlines all over the world. Simply asking "Are you worried about swine flu?" on your Twitter could generate hundreds of responses from your followers. Each response is then seen by anyone who is following the responder, and that's a great way to increase your Twitter traffic.