Jamie Zawinski, one of the developers responsible for the early versions Netscape Navigator, has declared that today is Run Some Old Web Browsers Day. In celebration, he's hosting an archive of old Mosaic/Netscape broswers and rolled back the clock on the original mcom.com domain.
home.mcom.com and all URLs under it just redirected to netscape.com, then redirected a dozen more times before taking you to some AOL portal page. The old URLs that were baked into the toolbar buttons of the original web browsers didn't work any more. But now, if you fire up a copy of Mosaic Netscape 0.9, and click on the various toolbar buttons, they will work again! For example, in the old browsers, when you clicked on the "What's New" toolbar button, it went here.
home.mcom.com is now a snapshot of that web site from 21-Oct-1994.
mosaic.mcom.com is now a snapshot of that web site from July 1994. That's from just after the company was announced, but before the first browser beta was released. I think that by Oct 1994, both mosaic.mcom.com and www.mcom.com were redirects to home.mcom.com, but I can't remember any more.
Evolt also maintains an extensive archive of browsers old and new. I have a smaller archive that I put together for an episode of 0sil8 more than 10 years ago.