I mean, obviously there must be a lot more going on inside twitter besides being a massive many-to-many pubsub messaging infrastructure. And frankly twitter can be improved by leaving a lot of stuff out and up to the client app, so it's not entirely unreasonabl?

> In one incident, he wrote, an error caused every user to log in as somebody else each time they refreshed the page.

Gotta admit, this story raised my eyebrow, this wasn't the dark ages of the web. What sort of crazy experimental authentication voodoo were they running?