Which is perfectly okay for the regular twitter web client, but we're talking about a single tweet status here, i.e. a page where you arrive by clicking on a link like "Bob Bobson recently stated that frobnication is all gonked up". Then you want to read the full 140 characters of what Bob Bobson said, and whoops, two megabytes.

(Never mind that at least for me, tweets are increasingly often turning up as search engine hits)