I had an interesting idea that I’d like to share. It would probably take some work to implement, so perhaps it’s best left for Danbooru 2.
I’ve seen a few comments that go something like, “man, this post is so gorgeous that I wish there was some kind of super-favorites I could add it to!” The basic problem is that as your favorites collection grows, the significance of adding a post to it lessens. This is especially true for people like Claverhouse or asianprostitute1500 who have literally faved over 10% of Danbooru. Unless you’re really stingy about faving, there really isn’t any way to express a level of appreciation greater than just “I like this picture” without waxing hyperbolic in the comments, which is stupid.
I think it would be pretty neat if we had a system where users could designate a limited number of posts, say five, as their top favorites. Users who have top-faved a post could maybe appear in bold in the Favorited By list, or maybe be listed separately. Since you would only have five of them, adding a post to your top favorites would be a very convincing way to express not just “I like this picture,” but “this really is one of the most amazing pictures I’ve ever seen!” Shown on your profile page, it would provide a very nice at-a-glance view of the sort of pictures you appreciate most.
Not only would it be nice from an appreciation perspective, but since it would actually force users to really think about a post’s quality, I think it would make a great search metric for finding quality posts.
Updated