What are quests?
Quests are activities that allow you to earn points by completing them. (You did the activities before, they just weren't wrapped in a Quest)
Quests vs Seasons?
Quests simply replace the various methods of earning points around the site and bring them all into the one page. So you don't need to visit the share, vids and other pages to find how to earn points, you just go to the quests page and they're all there together.
I completed a quest but did not get my points. What should I do?
Don't worry. We've written about this, and what to do, on the help center.