I have been trying to find a game just like this from the mid 2000s for years now. I think it was called something like Qwyzle? I recall the format of the game being identical to this, of individual html pages and there were Facebook groups of working out of the 100 clues.
I recall GEB (Gödel Escher Bach) playing a key part in a lot of the puzzles?
A big part of my early internet experience sadly lost