The legal landscape has also changed. 20 years ago I helped run a web forum, but with today's legal landscape - DMCA in the US, various different laws in the EU and other countries - I would never do so. The amount of liability on the host for user-created content is far too high.

The legal landscape has also changed.

It did change a lot but the biggest changes were the ToS/AuP of server/VM providers. What was not even taboo in the early 00's was becoming a problem keeping an account active on clear-web sites. Across the board many providers starting using the vague word "lewd" a word I had never heard of even after running porn sites for a long time.

Many of us moved to .onion despite being incredibly slow at the time. We would keep an unpublished clear-web sub-domain active for the old time users so they had a fast connection. Eventually that was even problematic so many forum operators stopped accepting new users and made their forums private or semi-private. Some still exist and some got married, had kids and real life took too much time and energy to also run such sites.

You are shielded from liability if you respond to abuse reports.

DMCA was already a thing 20 years ago?