[Twitter breaks] because “it wasn’t built right — Twitter was built kind of as a hack and they didn’t really architect it to scale and they’ve never been able to catch up.” – Fred Wilson
This is wrong.
Twitter wasn’t built as a hack, it was just built. The way you or I might build something new, in a couple of weeks, with some databases, and a couple of cron jobs, and a daemon or three. If they had built it [portentous voice]TO BE TWITTER[/portentous voice] they would have failed.
Scaling is always a catch up game. Only way its ever worked. If you never catch up then something isn’t working, but it isn’t original sin.