No doubt there's an excellent reason why the T changed its Twitter handle tonight from @mbta to @MBTATRANSIT. They might want to fix the Twitter link on mbta.com, though.
UPDATE, 8 a.m., Tuesday: It might not have been the T's doing. The Globe reports the T is trying to resolve "a technical issue" with Twitter - to the point of publicly tweeting at Twitter's support handle. Nat V. reports that when he tried to snag @mbta, he got back an error message that it was "too short."