you could say that about almost anything online, though. whoops, wikipedia went out of business and now we've lost a lot of information. oh darn, wordpress went down for good and took all its hosted blogs and the infinite wisdom found within their content.

that is an issue with the internet at large, not just with url shorteners. in addition, the only externally meaningful thing that would be lost is the bitly connection on twitter that connects that tweet to the content. whatever brilliance he linked to would still exist outside that scope and be accessible. unless his bitly link was to bitly itself.