What I do when I see a thread/post/picture I might consider as a "___ of the Year" nominee, I just put the phrase "___ of the Year(?)" somewhere in the post. That way, I can just search that phrase when nominations roll around.
This is a horrible, terrible, miserable idea. By posting, "Post of the Year!" after a particularly riotous post, you prevent any humorous follow-up. You have killed the joke. Nay, you have
aborted the joke.