"It makes me think that the karma system itself might be fatally flawed for its lack of scalability."

The motivation to be part of an online community should be the enjoyment at the discussions and not the number of points.

I hate the points, and I hate it, that I look after them. I think that just the presence of a karma system has a bad effect on the quality of the comments. You're getting what you ask for.

It's symptomatic how often I read 'Please don't downvote me' or 'I hate to say this, but' in the last time.