The ability to create apps like http://www.tweespeed.com/ as a result of a few quick APIs to get the difference between two status IDs is really nice.
Perhaps even if status IDs are not sequential there could be some kind of a an API method like tweetCount(firstID, secondID) that if given two statusIDs the API returns the number of tweets between these two? -- To unsubscribe, reply using "remove me" as the subject.
