Just idle curiosity, but has there ever been any research as to how long the average web-site lasts? Sure there are some monoliths like Amazon, or the Straight Dope that last forever, and sites attached to outside agencies (the site for NYU or any other college for example.) But what about your average run-of-the-mill fansite or blog, or odd quirky site that comes, perhaps gets a certain amount of fame / notoriety, and then one day no longer exists.
With the internet going on at least 20 years now, I would imagine that someone, somewhere has been compiling data on this subject.