when was this added in, and what does it change?
reputation
Races who hate you from reputation will likely attack you on sight (talking mobiles here).
It's only present on certain classes. That may be why you haven't seen it before.
It's only present on certain classes. That may be why you haven't seen it before.
Really? I mean, I haven't really been paying attention to it, but I've noticed reputation changes on a bunch of characters.
Actually I thought all classes have it. Typing "reputation" for any class brings it up, though only rangers have a permanent Hate to a race of their choice. For other classes you have to kill bajillions of the same race type in order for your reputation to go down.
All classes have it, only a certain one can pick a race they ALWAYS hate.
Try ranking in the tombs for 10 ranks or so and tell me rep doesn't change 
You don't even need one rank to really have it go to hate. All you need to do is kill enough of them in a short period of time and it drops pretty quickly. I went from excellent in halfling and Vampire races and dropped them both to bad within a matter of like 30 minutes. And then it took 8 times as long it seemed to get them back up to excellent again.
People don't forget easily. Try training charge/backstabs/ambush in elemental, that'll be a mistake you don't make again.
or try picking Human as your racial enemy when rolling a ranger and not really understand what that entails until you've ranked to about 30. then realizing you might as well delete.