A huge portion of tweets in my stream have a hyperlink anyway, so in some sense the "bandwidth" is much more than 140 characters per tweet. I think they could a

A huge portion of tweets in my stream have a hyperlink anyway, so in some sense the "bandwidth" is much more than 140 characters per tweet. I think they could allow longer tweets without compromising much. Perhaps the compose tweet text box could even indicate what is "above the fold," which would be limited to 140 characters.