A comment function would be awesome! Personally I think it is kind of useless to give points without telling why. If I give you a pat on the back you would also like to hear why I gave you a pat on the back. Same if I told you that you suck...you would like to know why so you could improve.
All comments a users has received should be viewable in the profile and maybe all comments the user has given as well.
It would be nice if it said something like this:
X has received the following comment in the thread "I feel good": blah blah blah