Friday, 10 April 2009

Could URL shorteners break the Web?

Many of us use URL shorteners like and For Twitter they are well-nigh essential, if you're not to use up your whole 140 character quota with a single URL.

I think it was Euan Semple in his Twitter incarnation @euan, who originally alerted me to the idea that these shortener sites might be a risk to the architecture of the web. As every schoolboy knows, the Internet was designed to continue functioning after major structural damage, such as that which might follow a nuclear war. It does this by virtue of its addressing system, which allows messages, in the form of 'packets', to be routed through many possible pathways, so that they always get through even if some pathways are blocked. Unfortunately URL shortening might be able to jeopardise this welcome redundancy. Shortening works (I think - correct me if wrong) by the storage on the shortener's server of a match between the shortened URL and the original one. Someone who clicks on the short URL gets redirected to the original (long) one. In theory, if a shortener's server went offline, because for example the shortener went bust, all the links would be lost.

What's to be done? There are a number of shorteners, so using a range of them reduces the consequences of failure of any one of them. But the impact could still be significant, especially if the most popular one failed. And the more paranoid might even see possibilities of duress here, should a shortener fall under the control of an ill-intentioned person. Admittedly the consequences of failure of any 'cloud' service, including good old webmail, could have serious consequences, but those are arguably less systemic than shortener failure would be.

Should there be some sort of process for putting URL shortener databases into escrow, or is there another answer, perhaps?