I read that FO: NV will have both a Karma system and a Reputation system separate of eachother. Will Karma reward/punish people? Good Karma would be seen as a lot of helping hands in the gameplay, but would htere be any benefit, and thus a reason, to bad karma?

Being evil adds, personality, personality, so many ways to add it everyday, stealing, raiding, your gonna love it when people are despising you, with real american badassness, it adds somethin to do!!

Anyone like my diddy for being evil?

Not altogether. That was a diddy? We need a musical note emote for situations like that.
Anyway...
Karma is more personal~ Whereas reputation is how the people will know you. For instance, you can be an evil jerk karma-wise, but people will still give you praise because you're the guy who stopped that one psycho from blowing up the water reserves in that one town, even if only it was because you yourself need water.

isn't reputation where people know you? I think if they praised you then it would be good karma.

Can I blow up the water reserves and then blame that 'psycho' and still have the town praise me?
I'm sure we'll be able to commit evil acts secretly and then pass our selves off as the good guy, but what about the opposite?
How neato would it be to be able to play a 'good' character that everyone thinks is the bad-guy.... You go outta town to save the water reserves from being blasted, you even talk the psycho out of doing it... All's well right? You get back to town and the psycho has been spreading rumours that you are stealing the water reserves and selling them the the local raiders... Everyone in town starts giviing you the stink-eye...

Well, the Reputation you have with them is good, that's why they praise you. But on your sparetime you're eating babies, which gives you evil karma, but no one knows about this so no one can judge you when you save the town from that psycho, like an old man walks up to you and say "well, I don't care if you saved us and all, I can still feel you're evil!"

Why would the game programmers do something like that?

You could also have a good reputation with a group of baddies such as slavers...you would have to do evil acts in order to increase your reputation with them.

We have open discussion about the Karma system http://www.gamesas.com/index.php?/topic/1086123-has-playing-neutral-been-reworked/

No need for two threads to discuss the same thing.