I'm not sure if this is right, but from what I've heard about the Karma system, it's similar to the merit system, and + Karma is only granted to useful posts, so being active doesn't help much. One could be here for 2-3 years and still struggle to get some, while another could be here for a few weeks and get a lot of + Karmas, so it's all about quality, just as on the other forum. Although the Karma system can be abuse easily given that any high-ranking account is able to give one while not receiving any (I gave out one +Karma while having zero Karma)
When a user is active it is supposed to be to contribute quality conversations and opinions, not to do nothing, which is why I don't agree with you 100%.
We're partially saying the same thing here ; Karma is not earned based on activities but quality contributions, if I look around I'm likely going to see active accounts with bunch of posts and no single positive karma.
As for the karma system, it cannot be easily manipulated as you say, since it has restrictions. Each user can only give 1 positive or negative karma to the same user every 10 hours. In case a user receives a lot of negative or positive karma, the administrator will be able to see it in the logs and take necessary action.
I got abused (Karma)on my first day here and admin came to my rescue. I like.it.
The number of posts by a user does not have much relevance, since what should prevail is the quality of those posts. Users with many posts and little karma are usually users who post LQP with the sole purpose of increasing their account rank in order to participate in signature campaigns.
Just because you've received 1 or 2 negative karma doesn't mean the system has been rigged against you, it just means, from what I've read, that your reputation (deserved or not) precedes you. The negative karma probably comes from some BTT user who is on this forum, but don't give it too much importance. You should already know that if you (or any user) receive karma abuse, the administrator can put things back in their place, and the author or authors of that abuse will be punished.