This document analyzes Twitter as both a social network and a news media platform. It summarizes a study of Twitter data from June 2009 which found: - Information spreads very quickly on Twitter, with most retweets occurring within an hour and retweet trees rarely exceeding a depth of 6 layers. - While a few users have over a million followers, the average number of followers and tweets follows a power law distribution, with a few highly connected users. - Retweets are an effective way for information to spread to a wide audience, with the median retweet reaching more people than the average tweet. However, people tend to retweet only a small subset of their followers.