The document discusses various statistics about Twitter usage such as the average time spent on Twitter per month (170 minutes), the percentage of monthly active users that actually tweet (56%), and the percentage using mobile devices to tweet (80%). It also discusses Twitter advertising costs and effectiveness compared to Facebook. The document notes that the 140 character limit was based on messaging protocols and that 20 extra characters were reserved for handles. It provides several lessons for brands on Twitter including the importance of attention to detail, not mixing business and personal accounts, personalizing your content, and being able to make a great comeback.