Somebody wrote a rant about how "karma" is a load of shit and it's being passed around Facebook like a virus. It's amusing, I guess, but the author doesn't understand karma, thus misses the point entirely.
Karma is based on a simple Buddhist principle, but can be pretty complex in concept (which is the opposite of how things usually work). So when somebody inaccurately boils karma down to "Do good and you'll receive good in return. Do bad and you'll receive bad in return"... then gets all pissed off because they think they're doing nothing but good but receiving nothing but bad... while people they perceive as "evil" are doing mostly bad stuff and yet only good things seem to happen for them. Well, yeah... it's frustrating, I know. But that's not the way actual "karma" works, and ranting otherwise is kind of silly. It's like being upset that your dishwasher can't play CDs or something*.
In any event, karma can mean different things to different people, so I suppose there's no "right answer"... but any answer people arrive at should at least be an informed one, and I'm not seeing much of that.
To me, karma is not some kind of cosmic competition where your good deeds and bad deeds are weighed against each other for points, then measured against other people's points to determine who gets to have good things happen to them. Buddhism doesn't have a deity to do the math required, so the idea of karma being some kind of "cosmic judgement" doesn't really fit.
So what is it then?
Karma is cause and effect.
• Greet somebody with a smile, and they will probably be react with kindness.
• Greet somebody with a punch in the face, and they will probably react very differently.
Now, those are obviously simplistic examples. Some people are assholes and all the smiles in the world aren't going to make them treat you kindly... but the principle of cause and effect being illustrated is what karma is all about. And when you look at it in those terms, that's where Buddhists find truth in the guiding philosophy behind their faith...
• Positive actions result in happiness.
• Negative actions result in suffering.
Note that I did not say "Positive actions result in your happiness" or "Negative actions result in your suffering"... and this is where most people who are tossing "karma" around get it wrong. They expect that their actions, positive or negative, have consequences, good or bad, that will reflect back on them... usually in some physically measurable way...
• I don't spread gossip and I found a penny on the sidewalk! It's karma!
• I have a positive attitude and I won a new car! It's karma!
• I drunkenly peed on my best friend's dog and I got stung by a bee! It's karma!
I'm not saying that there's no physically measurable payoff for what you put out there... obviously there can be... but most times that's not the case at all. Perhaps your positive action pays off for you, but only mentally or spiritually. Perhaps your positive action pays off for somebody else. Perhaps your positive action won't have any immediate effect at all, and it will be years before there's any kind of payoff. Whatever. It's the fact that there is a payoff... some time, some how, some way... that defines the cause and effect of karma.
Whether that payoff is something negative or positive is up to you. Or, to be more precise, up to the intent of your actions (that's a very Buddhist thing to say).
So go out there and make good karma by doing something positive!
That way I can wallow in negativity and bitterness over the crappy day I just had and know that some kind of payoff in goodness is happening somewhere.
Which will make my day a little less bitter and crappy.
See? That's karma in action.
*But wouldn't it be cool if your dishwasher could play CDs? Music while you wash your soup bowls!