It's silly but if those little "pats on the back" didn't exist, I wouldn't have stuck around CHUD for longer than two months, much less two years.
In the beginning, making quips on the board became my new video game, relegating my 360 to the dustbin. Over time, the accumulation of points began to blow new air into the long dead balloon of my self-confidence. Prior to CHUD, I'd never thought of myself as being someone to whom the adjectives "witty", "funny", or even "kinda smart" might apply. But because of those green thumbs in the corner, that's something I've come to actually believe might be the case. This in turn, gave me the confidence to engage in the world in ways I'd long been reluctant to. I've become quite the extrovert because of my time here, come to think of it.
In the macro sense, I'd say that the point system has served as a measure of quality control, providing a compass of sorts that allow people to stop & consider for a second that what they're saying might be of value. I know that's case with me, anyway.