I think XP is overrated. Don't get me wrong, I understand your sentiment, but I do not think it is worth putting in more effort into enhancing something that is meant more for amusement than anything concrete.

If you really like a post, then a private message to the poster would be probably most appropriate. You could also post a public reply saying that you liked it and why. Who knows, you might even pickup some XP with that post :)

Just my 2 cents