If I remember correctly in early Stack Overflow down-voting did cost your own reputation points, so every down-vote reduced your own reputation. I liked this and I claim it socialized me in a way that I rarely down-vote even today and even on other platforms like HN. I like to imagine that every down-vote lowers my own reputation even if that isn't expressed in points and even if no one knows. Every down-vote is a trade-off where I feel the benefit of expressing my own negative opinion outweighs my own reputation loss.

Obviously the system didn't work for Stack Overflow, otherwise they wouldn't have abandoned it, I don't remember why.

EDIT:

Seems the system is still in place. Down-voting an answer costs one reputation point, down-voting a question is free.[1] For reasons for the asymmetry see [2].

[1] https://meta.stackexchange.com/questions/7237/how-does-reput...

[2] https://meta.stackoverflow.com/questions/251610/why-does-dow...