This document provides an overview and introduction to Twitter. It begins with an agenda for the presentation, which includes a crash course on Twitter, examples of its uses, and an explanation of related technologies like blogging and RSS. The presentation then defines Twitter as a free social networking and microblogging service that allows users to post short messages. Examples of how Twitter is used at RIT are given. The rapid growth of Twitter is also noted. The document concludes by discussing related concepts like hashtags and mentions and encouraging attendees to try out Twitter themselves.