1. The live stream is the point of Twitter. Notice how the major search engines made agreements with Twitter to get up-to-the-second results. 2. "in reply to".

1. The live stream is the point of Twitter. Notice how the major search engines made agreements with Twitter to get up-to-the-second results. 2. "in reply to"...right there on twitter.com, and any halfway decent client. 3. Retweets and favorites allow you to recommend/rate individual tweets. EDIT: swombat already posted these points before me :/