Ha!
that betrays your tender young age my friend...
at the beginning of the internet, when we old farts used Macs 512 with dial-in modems and used diskettes, Compuserve was a site that hosted a plethora of different newsgroups of various interests. I went there to search and read threads regarding my interests, in this case digital audio (if such a group existed then) or maybe MIDI, etc.
Compuserve vanished forever maybe fifteen years ago. I doubt there's any archive of that.
Regarding "MixDown CBX-D5 Demo", I downloaded this package in 1999. It was, as the name says, a demo: some functions didn't work, and the authorization cost was high ($120 Australian dollars), so I didn't buy it. I don't know if the version that's pointed to is unlocked, I'll have to check that. I have now dismantled my historic setup cause I needed the space, so that won't be anytime soon.