What your requisits to rate a discussion of someone?

I usually award all discussions with a + rating but occasionall i will give a - if i think the person has stolen someone elses discussion, broken rules or if they have not put any effort in to the discussion, like the ones where people write 1 line in the title & the exact same line in the discussion - making the question only a few words long. I also don't rate highly, the people who just post discussion after discussion because they think they can make a lot of money doing that.