I think there should be a way to get notifications when things are added to collections.

This could be either a favorite button that works like other submissions (It allows you to get notifications when the submission is updated), or it could be a follow button, like the one that tickets have.

This'd be helpful because if there's a collection of things you really like, you could favorite/follow the collection and get a notification when more is added to it.

Specifically I think this would be great for things like contests, like if you're a judge of the contest, you'll get a notification when a new entry is added that you need to look at. It would also be great for PMC Weekly parodies, like PSNN.

EDIT:

After giving this a little bit more thought, I think that a follow button would be better than a favorite button.

Favorites are more used to show your support, so some people might favorite a collection just to show that they like it, but not want to get notifications from it. While on the other hand, follow buttons aren't really used to show support, so they'd just be used by people who want the notifications.