Google Groups’ 20 Year Usenet Timeline
This has probably been on Google for a zillion years and I just never noticed it. Its a timeline of Usenet history with links to significant posts inside the Google (dejanews) usenet archives.
Fortunately Google does not have my first Usenet post (circa 1986?), which is good because it was really, really embarrassing. (and watch, now someone will dig it up just to horrify me)
(I got it from The popular links on del.icio.us.)