bs1011

It's mostly by the employees of the respective companies themselves. I once was working in a company (now a popular help desk company, famous within HN circles even) where the co/founder called up a few of his employees to downvote a comment that raised a serious but negative tone about his company. And all the employees were smart enough to use proxies to downvote the comment into oblivion. So, always think twice if it's worth losing your karma in a fixed game.