(I posted about this once before, but I'm posting again because I made a revision to my original idea.)
There's a lot of pictures on this site that are severely lacking when it comes to tags (like, they only have half a dozen or so, maybe less). My original idea was to create some type of program that would automatically add tagme to any picture with less than a certain number of tags, but that might be hard for the moderators to come up with such a program, and what the threshold should be would probably be heavily debated.
My new idea is to just have tagme be in the tag box as a default whenever someone uploads a new image.
If the uploader wants to fill in the tags for their upload, they can take tagme out.
If they don't have the time or energy to add tags right then, they can leave it in so someone else can do it later.
If they don't want to fill in the tags for their upload but take tagme out anyway, they're an asshole.
Updated