I asked this question on August 4th, and just got a reply today (August 9th). To support the answerer, I upvoted his/her answer. I am not ready to choose it as the best answer, but I will likely select it if no one else answers.
However, upon upvoting his/her answer, I got +5 reputation. Usually you don't get any reputation for upvoting any questions or answers, so why did I get +5?