Whats the point of having separate rules for collections/challenges?
The rules are basically the same as for everything else on the Archive. This just allows another way to group fanworks by areas of interest. There is one important special rule: if the collection maintainer says in the rules that submissions are final, then you can’t withdraw your contribution from the collection, though you can always orphan it. We put this rule in place to allow gift exchanges. Ordinarily, removing a fanwork from the archive is sad, but it’s up to you. But when you’ve added a fanwork as a gift, and possibly received a fanwork as a gift in return, we think it’s fair to say that the other participants should continue to enjoy the benefit of your contribution. In those cases, orphaning allows you to sever your connection with the fanwork while not removing it from the collection. This policy was based on prior experience with the Yuletide Rare Fandoms gift exchange.