Your rating and karma don't really affect you at all, it's just an outward expression of how much you have contributed to the forums, and the quality of your posts. Other users change your karma by clicking the little thumbs up or down underneath your rating on each post. (Not visible to you, but you can see it on others' posts, like this one)

And as far as asking all these questions go, if you happen to have any more could you please post about in one of the (3?) topics you have already created, no need to create a new topic for a simple question.

In general, people rate people down if their posts look rude or very low quality and they rate you up for big project updates, good help given to other members and particularly funny jokes. But it depends of the person and don't worry, your life won't depend on your score. (Although people tend to reply less to your projects if your negative score is too high because they'll be scared)

In general yes, because people tend to rate low quality posts less than mean ones from experience. If you are not mean but your posts are always on the spammy side, you'll just remain stuck around +1/-1 forever or so.

When an user is often mean or try to cause drama, what I notice is that they get less replies for a while to their topics.

If you are not mean but your posts are always on the spammy side, you'll just remain stuck around +1/-1 forever or so.

Like me for my first 5 months