[Gunax]

You get karma for posting pithy and non-controversial (pessimists might say groupthink agreeable) comments or posts.

As much as everyone claims the system is for rewarding on topic discussion, in reality it is used to award points to people who echo whatever is popular and to put wrong think at the bottom.

[popinman322]

You can convey unpopular opinions on Reddit without getting downvoted. It just takes good wording and replying to the right post-- essentially what's required in real life: timing and tactfulness.