As someone who is more or a listener than a talker I sometimes find it difficult to comment on posts but still want to acknowledge that I've read them. So some DW form of 'I appreciate this' box would be totally awesome as far as I'm concerned.

I really like the idea of allowing people turn to them on and off on their own journal. That way if you're someone who really hates the feature at least you don't have to see it in your own space.