Due to various reasons I seldom comment, so Kudos for me are a way to leave a positive feedback I wouldn't have left otherwise. It means anything from "This story has some problems, but I enjoyed something in it" to "I like this story so much I have no idea what to say".

It has also made me more likely to leave a comment, as it takes the scary out of commenting and means I have a feedback fallback without feeling guilty that I commented on one story but not another.

I'd also like chapter kudos back, because I would like to say "Still reading, please write more" without having to either say that phrase every chapter or having to come up with something new each chapter, even if I don't have anything to say at the moment.