This document provides an introduction and overview of Twitter, including: - Twitter allows users to post and read short messages called tweets that are up to 140 characters - As of 2015, Twitter had over 300 million active monthly users who can follow accounts and see tweets in their timeline - Common types of tweets include news, spam, self-promotion, casual conversation, and sharing valuable information - Key Twitter terminology includes tweets, following, timelines, @replies, retweets, hashtags, and direct messages - Compared to blogs and chat, Twitter enables more simple, quick, frequent, and personal communication