Tornado is a real-time web server built in Python that supports tens of thousands of continuous connections and thus the long-polling method of real-time data delivery. It is the core of FriendFeed, a technically innovative service built by two ex-Googlers and leaders in the real-time web community, which was acquired by Facebook in August, 2009. Built largely by the man who is now CTO of Facebook, Bret Taylor, this first version of Tornado was taken across the finish line by another heavy hitter: Ben Darnell of Thing Labs.
Ben Darnell was a key engineer in building Google Reader years ago, then joined real-time aggregation startup FriendFeed with Taylor. After FriendFeed was acquired by Facebook, Darnell rejoined Thing Labs, makers of Brizzly and lead by Google Reader's Jason Shellen. In the meantime, he's been helping bring Tornado to its 1.0 and now that time has come.
Below is a clip of Facebook's Bret Taylor explaining Tornado on the Gillmor Gang podcast, the day the open sourcing of the technology was announced.