Google Groups offered an early Usenet search "going back to 1980," but today I can only get results back to 2000. Maybe it's a blip, or a UI change, or maybe they silently killed off the archive (I hope not, after all that great press about preserving open access to digital history).
Was this news at some point and I just missed it?
[1] http://news.bbc.co.uk/2/hi/science/nature/1709527.stm
[2] http://itools.com/tool/google-groups-usenet-newsgroup-search
[3] Google Groups Usenet Timeline is now a dead link: http://www.good-stuff.co.uk/useful/google_usenet_timeline.php
[4] http://www.salon.com/2002/01/08/saving_usenet/