Google has finally integrated some 20 years of Usenet archives into Google Groups. (Usenet, for those who don't know, is essentially newsgroups; it's funny, because so many people don't know what they are now, but back in the early days of the Internet, newsgroups on various topics were these amazing communities of like-minded people, sharing information on every topic imaginable). Because this archive goes back so far, you can find such posts as...
First mention of Microsoft (May 1981)
First mention of Star Wars Episode 6, then called Revenge of the Jedi. This post reads like a precursor to Ain't It Cool News, albeit minus the foul-mouthed fanboys and large (both physically and personality-wise) moderator Harry Knowles.
First mention of Microsoft Windows, an operating system for personal computers made by Microsoft Inc. of Bellevue, Wash."
First announcement of the Challenger tragedy. Tasteful post to net.space.
First mention of AOL, which I didn't realize had early early links to Apple.
Tim Berners-Lee announcing his WorldWideWeb project.
Marc Andreessen announces Mosaic, the first web browser.
Linus Torvalds announces Linux.
What's really fun is trolling for my own early posts. Finding them out there and reading them is a complete nostalgia trip. The earliest post that I wrote is from 1993. Here I am, in 1994, begging some hometown fans for news on my beloved Cubs. I write: "Steve Traschel--his stats look impressive. I can't wait to see him pitch. What kind of stuff does he have, and is he for real?"
I didn't really post to Usenet that much in school. I remember reading a lot more than writing. I do remember printing out some of the early FAQ's off Stanford's networked printers, carrying off 400 page printouts of the complete annotations to Milton's Paradise Lost or Neil Gaiman's Sandman, crazy things like that. All plain ASCII text.