Now that we have public collections, it would be nice if it was possible for people to do stuff like "My best of 2012" or "Best selling releases of X week" or "Pitchfork's top 100 of the 1990s" or... well, you get the idea. This would need:

Some kind of ordering interface (which we could probably more or less reuse from ordered series once that's implemented).
Either a flag (ordered/unordered) so that order stuff isn't loaded where there's none, or just hide it if all position values are null.
A column "position" in the editor_collection_release table.