They would do it without a karma outcome, so adding karma seems unlikely to affect the overall number of comments much.
I don’t think that follows. I enjoy drinking soda, but if someone gave me $5 every time I did it, I would drink even more soda.
More directly, as a data point, I find myself commenting more on Less Wrong than on other blogs because of the karma points system. However, an even bigger motivator for me than that is the response notification; if not for that, I would almost never comment on old threads, or post comments specifically inviting response.
I don’t think that follows. I enjoy drinking soda, but if someone gave me $5 every time I did it, I would drink even more soda.
More directly, as a data point, I find myself commenting more on Less Wrong than on other blogs because of the karma points system. However, an even bigger motivator for me than that is the response notification; if not for that, I would almost never comment on old threads, or post comments specifically inviting response.