The Twitter growth numbers are amazing:

tweets

• 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 Year’s Day.

accounts

• 572,000. Number of new accounts created on March 12, 2011.
• 460,000. Average number of new accounts per day over the last month.
• 182%. Increase in number of mobile users over the past year.

#employees

• 8. 29. 130. 350. 400. Number of Twitter employees in Jan 2008, Jan 2009, Jan 2010, Jan 2011 and today.