I quit Twitter on 2010-06-29. It looks like I got out just in time too, everyone is complaining about the Whale!
2010-07-02 Investigating Elevated Error Rates 59 minutes ago
We’ve received reports of elevated error rates for users; we’re currently investigating.
Update (9:47 AM PST, 16:47 UTC): This is unplanned downtime. Infrastructure and operations engineers are working to fully restore Twitter. Expect more updates soon.
Update (9:55 AM PST, 16:55 UTC): We are now recovering from a period of high unavailability.
I'm guessing they have some folks over there who don't know what they're doing. They've had Fail Whale challenges now every day beginning the first part of June 2010. It is ongoing as of this moment. I think they're running Windows Servers out of their basement or something.