Twitter's 140 character limit has got users scrambling to find third-party URL shorteners. You have to copy your URL, find your shortener, paste in the URL, copy the shortned URL, go back to Twitter, paste in the shortened URL. (Or, you have to add yet another Firefox plug-in.)
Another issue surfaced this month when Trim announced that it was going out of business, which would have meant the breaking of user links. (Trim has since announced that they're staying in business after all.)
Twitter will often change and shorten URLs if they're already short enough to fit into 140 characters. Why not accept URLs of any length as long as the words plus the shortened URL fit?
Of course, this wouldn't work sending tweets directly via SMS. But who does that? Everyone's either using a Web page or a cell phone app. If the URL shortening service was as open and extensible as Twitter itself, the phone apps could tap into the URL shortening service as well.
Heck, charge me $5 per year for this. Totally worth it.