That is a REALLY interesting idea. You'd need to add something to encourage highly valued contributions. Like perhaps the comments are paid for with points (purchasable for money) but the submitter of a story gets "paid" 25% of the points spent on comments unless another person submitted the same story within 6 hours (in which case no one gets paid). Posters of comments also can get back the cost of their comment if it receives more than N upvotes (tweak N until it works).