tr.im was BY FAR the flakiest URL shortener out there. It seemed to me like it was down or overloaded as often as it was up. The biggest reason not to use tr.im isn't bogeyman partnerships between Twitter and bit.ly, but this:
Slashdot videos: Now with more Slashdot!
We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).