Twitter is a communications tool that allows you to communicate with others in 140 characters or less via the Internet or cell phone. People can "follow" you using Twitter -- and you can follow others -- as they share information and provide updates on business and relevant personal developments. In short, Twitter represents another vehicle for allowing others to get to know you and potentially form a mutually beneficial relationship. Check out this guide on how to use Twitter as a means of staying in touch with colleagues at your organization -- and how to build your personal profile.
And check out Guy Kawasaki's post on how to add followers on Twitter.