@rawsos: quest was a thing where you'd get points for visiting certain pages on the site, and more points for getting a particular set. Like you'd get points for looking at the page for each member of the Fantastic Four, and then more points when you looked at all of them. You'd level up depending on how many points you got.
@darkthunder: @rawsos: very old thing the site used to do. Basically it was their way of encouraging users to explore the site. They would have various quests for you to do that would involve tracking down certain pages via hints they give. Or the quest may require you to have a certain number of images in your gallery or have a certain number of posts. But basically they were more to encourage users to explore the site and be active. They had no real purpose. Probably why they got rid of them.