Does anyone remember when certain glitches were discovered?

[Dragon Arbock]

Was trying to find out when Glitch City and the Mew Trick were both discovered but a lot of the old net is no longer functioning.
The earliest reference to Glitch City I could find was in June 2000, in reference to an Azure Heights post. That post linked to another website that is now defunct and also not archived. Considering people were seemingly doing other Safari Zone exploits since 1998 at the least, I figured this would have been found sooner, but no such luck in proving that.
There's no reference to a working Mew glitch on here at all, except maybe one that pertains to the Select glitches in Pokemon Green, but that is not what I am referring to. In terms of what is now the standard methods (Long-range trainer, aka Trainer-fly glitch, and fighting the kid with the slowpoke), nothing comes up at all, though it seems likely that most discussion on this moved to forums after 2000.

[Picto Dev]

Wish I could help with an anecdotal story, but the first time I remember reading about Glitch City online was in early 2002, which is already after your earliest known date.
It wouldn't surprise me if it were around during the late 90's though, similar to "L is Real" and the backwards long-jump in Mario 64. I'm actually in a similar boat as you, trying to find some of the earliest mentions of "L is Real" online. (Of course, Usenet groups are the best go-to) Quick tangent, but everyone forgot that the number was typed "L is Real 2041" in the early years, I have no idea when it switched to "2401" as is dominant today. Maybe around 2006?

Back to Pokemon, sadly, it might have just all been on sites that weren't archived... or the playground. There was a concentrated effort to archive Geocities websites, but what about the more obscure web hosts of the 90's? I'm always wondering if they were on those sites instead.
Anyway, Google Groups is shutting down tomorrow, so if you want to reply by chance, my email's pictodev01 at gmail.com