How do you use Twitter to grow your business?

Twitter is a social network, like Facebook, but everything on Twitter is 100% public, 100% of the time. This makes it very useful for virtual networking. To participate on Twitter, you post short messages of up to 140 characters.Some people compare these to Facebook status updates, but that's not strictly true--you can use messages to broadcast all sorts of  useless, irrelevant, useful, relevant information. My messages are a mix of personal comments, responses to people I find who could use help with bookkeeping or Quickbooks, and links to things I think are interesting.