Stashed in: Square, @lizgannes, @evelynrusli
According to Evelyn Rusli's NYT Dealbook article on Square: http://dealbook.nytimes.com/2012/04/18/square-said-to-seek-250-million-investment/
Some previous Twitter stats I've stashed.
Note in particular Liz Gannes' excellent article on 4 tiers of Twitter users, which cited 100mm active users and 230mm tweets/day as of September 2011.
Lessons learned from Myspace
Perhaps now is the time to replace MySQL with MariaDB.
This Is Twitter's Plan To Get A Piece Of The $70 Billion Spent On TV Advertising