Treat people with some respect and have a sense of humor. Now, I know right off the bat, you're gonna say "Respect?!?" as if I am incapable of treating anyone kindly, but your experiences with me have been rather limited. Normally, when the humor clashes with the respect, it is viewed as irreverence and that is where you get into choppy waters. Some people have a shitty sense of humor and take themselves too seriously when they should realize this is a forum where individuality is king. Basically, if you cant take a joke, maybe you should look for a moderated forum. The cornerstone of a place like this is speech, and as a wise man once said, you have no right to be free from offense here.
I think this place works wonderfully as an experiment, you've got all different walks of life co-existing and the diversity of topics here reflects the diversity of the people themselves.
So, I think the secret to karma is to make some friends, be flexible enough to go up and down the "social scale" by participating in the topics both serious and light hearted. Have some fun, fuck around, and when it comes time to vocalize your opinion, dont bother checking the wind to see which direction it's blowing. Just stand up on your hind legs and sound off like you've got a pair.
...Because thats how life works, in general. So, its really not a secret at all, its more like a hidden truth. Its just as visible as someone standing right in front of you trying too hard to be liked. People like other people for thousands of reasons, but nobody likes a liar. You can craft your technique long and hard, but it'll still be fiction unless you drop the mask and just speak your mind. And, if you can do that with positive feedback... The answer to the question is pretty simple. You are being rewarded for being an enjoyable person, or the opposite. Of course, it does tend to get abused in some cases. Probably not yours, though.