Curious about what they are, I can't find an answer.

they're related to how much you have chatted on the forums. you can check out how close you are to each star. just scroll down to the forum posts part.

Thanks, ! How many stars are you able to get?

six is the maximum. c:

The stars aren't related to the achievement, you get one every 750 posts

Thanks a lot, ! That's really helpful.