If you piss someone off and they downvote all of your comments the score on the comment may become 0 or can be -ve.Karma is measured by how other redditors think about your contribution to the community.
But this is wrong social media websites are not just for entertainment but also are a great source of information and a source to promote and boost your businesses. Reddit is a social media forum that is a mass source of information and knowledge.
On Reddit you can find topics related to any subject.
I feel Reddit Karma is somehow related to Karma Yoga described in Bhagavad Gita.
In Bhagavad-Gita concept, karma is a store of good and bad actions, accumulated over time, and it is this store of actions that binds one to phenomenal existence.
Basically, all you do is go back to your earliest posts on Reddit (mine go back a little over 2 years now) and work your way forward reusing/repurposing your content along the way. Now, while I know many Redditors out there are rolling their eyes at the thought of reposts, here are a few points to consider: a) There's a good chance that TONS of people are on Reddit now who weren't before when you posted what you did a year or two (or longer) ago.