engine - 4:34 pm on Mar 21, 2011 (gmt 0)
It seems that the first ever tweet was today, 21 March https://twitter.com/jack/status/29#
3 years, 2 months and 1 day. The time it took from the first Tweet to the billionth Tweet.
1 week. The time it now takes for users to send a billion Tweets.
50 million. The average number of Tweets people sent per day, one year ago.
140 million. The average number of Tweets people sent per day, in the last month.
177 million. Tweets sent on March 11, 2011.
456. Tweets per second (TPS) when Michael Jackson died on June 25, 2009 (a record at that time).
6,939. Current TPS record, set 4 seconds after midnight in Japan on New Years Day.