Please don't comment on HN like you would on Reddit. If you don't have questions or information to add to the thread, you should probably use that as a cue to refrain from posting.
Joke posts might not seem bad, but in aggregate they lower the signal to noise ratio we have come to appreciate about HN. Additionally, once these kinds of jocular posts start, it becomes infectious.
I'm not trying to be mean; I'm guilty of making posts like this too. Many of us simply do not want to see HN devolve into the equivalent of a spammy subreddit. It's important that we all remind each other of the value of this community so that we can protect it from spiraling into a bad state.