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.
Except arbitrary URL shortening services are far more likely to shutdown than Wikipedia, Google, or Twitter itself. It's another level of indirection through another party which provides a service in a fast-changing, simple market.
Are all the URLs in your tweets going to be broken in 2 years? More likely than a Wikipedia or Google URL.
so are the twitter image hosts. or arbitrary S3 file hosts. or a wordpress mu blog network. or any number of other smaller alternatives for services that we deem useful.
i suppose the root of my problem with this line of thought is that it basically is saying that if you want to start a value-added service, go big or go home. no room for little guys, because if you fail you might somehow be destroying some of the fabric of the web.
i find this disagreeable. seems not very hacker-like.
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.