The “Internet Archive”:http://www.archive.org/ which has an index of 11bn web pages – snapshots of the web at various stages of its development – now has a “search engine”:http://www.archive.org/iathreads/post-view.php?id=8569 covering at least part of the archive. So you don’t need to know the precise address of the web page you had given up for lost (though that function still works). And you can see how the web saw things over time – you can see when a topic became “hot” for example – it provides supplementary graphs.
Thanks to “BoingBoing”:http://boingboing.net/2003_09_01_archive.html#106280030381534395 for the link