There's not much from the 90s at all really. While some stuff is there, most of the stuff I remember from the 90s isn't on archive.org and probably nowhere else, except maybe in someones old hard drives or floppy disks at the bottom of a drawer.
The main geocities-alike web host I used around IIRC 1998-2001 is just gone, as far as I can tell. I think it was called spree.com. The spaces were intended to be used by some kind of sales affiliates, I think, but were de facto just little ad-free (unlike other hosts) web spaces with a decent amount of storage (a few MB, I think?). I wasn't the only one just using it as free web hosting.
I've tried a couple times, and can find no record of the service ever having existed, let alone any of the content that was on it (mine, or any other).
And Usenet is pretty fragmentary as well and, even among what was preserved, I don't know how accessible what archives there are as they went via Dejanews and then Google Groups.
Of course, there's also a huge amount of information about companies, products, news, etc. that was largely never in electronic form and--where it didn't just get tossed in the trash in the wake of some corporate buyout--is in the stacks of some library someplace.
> I don't know how accessible what archives there are as they went via Dejanews and then Google Groups.
And unfortunately Google has starting blocking some groups because of too much spam (that to some extent probably was enabled by Google itself in the first place), and unfortunately that means that the archives of those groups (pre-dating the current spam deluge) are inaccessible, too.
Although there is not much of an archive of before 1996/1995 (it's lost)