I ran an Atari BBS in 1986-1987 in Houston, Texas area. It was called Atari Smallfry. Around 1998 I created a webpage with the same name. Mainly I just listed links to all the sites out there at the time. Since then I periodically check the links and see who is still out there. In my early days I was an 8-bit user and later the 16/32 with the different ST models.
I am sure there may be many new sites and I know many have gone away.