I post a lot I guess. I like to be involved in conversations with people who share my interests, and I like to argue, debate and critique. This isn't a professional forum and I don't think people should be discouraged from posting for fun.
I guess what I'm saying is, right now, for me? Karma points act as an inhibitor to my posting frequency. Honestly. I've had responses typed out, and erased them because I didn't want to rack up 15 meaningless karma points. I'd actually post more without them. I might be in the minority, but I really don't think anyone sits around laughing manically watching their karma total go up. I mean, seriously! Why would they?
However, I DO think that some people are naturally much more chatty, and just like in real life, that really rubs some people the wrong way. The same people who post, "Yep", or, (funny .gif) are probably the same people who will talk someone ears off at a party and they do so without being "awarded" karma points. The same people who are driven up the wall by that, probably hate it here too. There's an ignore feature if you think someone doesn't add anything to the forum and it's a lot easier to do than excusing yourself from an awkward Chatty Cathy.
I think it should either be stuffed, or, simply based on thumbs. I don't mind the conversational posters much. Sometimes I roll my eyes, but I never thumb those posts. I don't see anyone else doing so either. Vid's priceless technical posts? Some of gambit's more hilarious biting rebuffs? The occasional gif from Ted that's actually especially clever? I thumb those. I think at that point they've contributed more to the forum than is base line. I don't mind recognizing those people for such.