instead of a karma number, it would be better to have a different indicator. still count karma in the backend, but display only a percentile, or a number of symbols depending on the karma compared to other users on the platform. For example, relatively low karma would be `+`, high would be `+++`. Something that is very difficult to game and gameify, while still giving a nice little indicator of activity and whether someone's other comments are liked here.
Or just make the user karma a simple average over all their posts and comments. Anything but a straight number that goes up each time!
I use my own karma display as a way to check if its likely i have new replies.