After several iterations, revisions, down times, and false starts, I've finally relaunched BlastFollow in its own domain. It's a free tool that lets you auto-follow people who tweet with a specific hashtag. Just enter the hashtag and start following people who share your interests. The idea here is that people who share your interests will likely follow you back. The tool also allows you to unfollow people who aren't following you and refollow people who ARE following you. Check it out. Keep in mind if you follow too aggressively, your account will be suspended. So use the tool prudently.