I used to be the community manager for a StackOverflow-style (pre-dated SO by a number of years) site that catered to enterprise technology and we had ~200k-400k monthly visitors just on AS/400 topics — it was a huge and active community, but there was very little advertiser interest in it. A few years after I left, they completely shuttered the site and nuked the archives, sadly, so that's probably part of it — my site and others like it were bought up, monetized, then nuked when the money moved elsewhere.
The other partial reason is that a ton of those conversations happen in old email groups that aren't indexed or index a lot worse than spam sites do. So if you're interested, searching around for mailing lists, users groups, and old forums and there's still good material out there, just buried and mostly catering to folks who know the basics, so a bit tough to parse if you're new to it.
The other partial reason is that a ton of those conversations happen in old email groups that aren't indexed or index a lot worse than spam sites do. So if you're interested, searching around for mailing lists, users groups, and old forums and there's still good material out there, just buried and mostly catering to folks who know the basics, so a bit tough to parse if you're new to it.