You don't think mentioning that a joke is a "repost" is stupid? In the thread of each reposted joke, there are almost always a whole bunch of "Repost" messages. In other words, the "Repost" messages are reposted much, much more often than the joke. Many people who visit r/jokes have not seen the reposted joke before -- but unless you're a first-time visitor, you've seen the "Repost" messages probably hundreds of times before. Doesn't that make the "repost" messages vastly more annoying than the reposted joke? Also: what good does it do to mention a joke is reposted? Is it informative? Funny, interesting? And if OP's intent is to harvest some karma, would downvoting not be more efficient than commenting "repost"? I only see a joke when it's been upvoted many times, and yet, the corresponding thread has lots of "repost"-messages. Since it was upvoted many times, lots of people apparently enjoyed it -- but no one enjoyed the "repost"-messages.

How am I contributing? Well, I like to think that it may open the eyes of one of those people who post "repost" messages (already have, actually).