This is the point system that comes with q2a 1.5 and 1.6 (and older versions?) installed by default:
I thought it is time to rethink the system. I have found a quite good explanation, how and why stackoverflow chosed their point system:
An upvote brings the author +5 reputation if it"s a question and +10 reputation if it"s an answer. The difference is because answers are the ones that provide the highest quality content, so they are more valuable.
A downvote reduces the author"s reputation by 2 points, no matter if it"s a question or answer. However, when you downvote an answer, your reputation will also go down with 1 point. This decision was made to encourage improving the answers as opposed to just marking them as low quality.
Every question has to have tags: at least 1, at most 5. These tags help categorize the questions so they"ll be easier to sort and find. For example, a question about how to apply a Look-and-feel in Java will probably have the "java", "swing" and "look-and-feel" tags.
The question"s author is encouraged to pick an answer that he considers to be the best. In this case, the answer"s author receives +15 reputation and the question"s author receives +2 reputation.
from http://www.todaysoftmag.com/article/958/the-stackexchange-network
What should we modify?
