I've thought about this a little bit lately, and I've started to believe that it may be difficult to have both; if you let "funny" start to be valued, then it quickly overtakes the other values.

Having spent quite a bit of time on both Reddit comment threads and HN threads, sometimes on the same topics, I find the earnestness and thoughfulness of HN extremely refreshing. At reddit, I feel momentarily amused but then I'm left empty from the total flippancy and lack of substance.

I think that most of the “funny” comments usually decrease the signal to noise ratio. But I have a personal rule of not downvoting them when they are already gray. I only downvote gray comments if they are very offensive.

One of the things I love about HN is the lack of people trying to be funny. Between Twitter, Facebook, G+, <insert social media outlet>, there are plenty of places I can go to laugh. But HN is one of the few places where I can get top-notch news with input from a lot of smart people, as well as intelligent, civil discussions even when people disagree. I'm happier without the witty comments.

I agree with what people have already said, but I think there's one more point to add: people usually over-estimate how funny their own comments are. We have a tendency to think, "This idea of mine is hilarious! And different! Surely this witticism is the exception." And we are usually wrong. When you have N people all doing that, there's a lot of noise.

I try to gently point this out to people who complain when their attempt at humor has been downvoted by the community. It's not that we don't like humor. We just don't like banal attempts at humor, which becomes noise. Or, put in a less charitable fashion, "You're not as funny as you think you are."

On HN, humour is almost only ever desired if it's in combination with other content. If someone injecting a bit of humour is not quickly downvoted, then others start throwing out their "witticisms" and things degrade rather quickly. Better to nip it in the bud and potentially upset someone making an innocent comment than to have things overrun.

I think people want high SNR value before a clever triple entendre, but accomplishing both is far better. Failing that, expressing a clear, reasoned sentiment is also another tact.

I've found the voting to be a great measure of what's hilarious. Whereas comments that are only moderately funny or diverge into off-topic are usually heavily downvoted. So, I think the threshold is just very high for jokes.