Around 2007-2009, I was introduced to a website which hid puzzle clues in website data such as picture code as well as normal puzzles using various different types of code breaking and cyphers. The goal was to find the next url to progress with the puzzle. The puzzle eventually ended as the site was not being updated and it even had a forum for help along the way. Any ideas on what the site was and if it still exists?
The riddle series you were looking for was Tricky's Riddles. It's an old puzzler that I myself came across in 2006 back when a bunch of my middle-school friends introduced me to it, and back when it didn't have a domain and was still being hosted in a University of Exeter home directory. Looking back at it, the riddles were really shoddy and much too "random", but back then it was the ultimate challenge for us.