This document discusses how Twitter can be used by teachers to expand learning. It provides an overview of Twitter, including what tweets are, how to join Twitter, how to decide who to follow, and common Twitter terms like mentions, retweets, and hashtags. The document then discusses how teachers can create a personal learning network on Twitter and offers various ways Twitter can be used for teaching and learning both in and outside the classroom, such as for class discussions, feedback, and investigating related topics. Specific strategies are proposed, like having students tweet about themselves or course topics. In the end, readers are instructed to tweet about themselves using a hashtag to connect with others.