Hello! I actually recognize you from the message board!
I've attempted asking Vimm on the message board, Sadly i didn't get a response. I was curious because I agree, the fact he has kept it alive for 25 years is truly remarkable.
Most Rom sites do that too. The site Romnation only has snes and nes roms but Nintendo still took them down. so how could vimm do the same and not get took down? Maybe its servers are located out of the country.