That is a good suggestion, but I still like the idea of how karma is given on Reddit, that there's an indication of whether you give karma to specific posts and the number of karma it receives. Although you can add and remove the karma there without time restrictions unlike here. The 10 hours time restriction is also a bit disappointing IMO, that it's too long for me and it should be post-based, not user-based. What I mean is you can give karma to a user on his different posts, 1 karma for every specific post. Now since you can give karma in PM pages, then it should be once there for a certain time.