Is there a way to see who has given the reputation comments? In the "Latest Reputation Received" box in the user cp there are just three fields (Thread, Date, Comment). It doesn´t say who has given the reputation.

I think there is if they leave their name

Yes they have to leave their name. I will look to see if there is a way around that.

Some forums show you who left the rep. Don't know if that can be done with this software, but it would be nice.

I would assume that the point behind leaving it anonymous is because they're allowed to give you negative reputation as well, and I would think they wouldn't want to engender retaliation by knowing who left you "negative karma" so to speak.

I could see them at YDG, but I don't remember if that was always the case or just when I became a moderator. May just be a setting to show the username to everyone. You should be able to ask an Admin at least if anyone leaves any inappropriate comments through the rep.