'Gamification' of social media websites has been the current trend for a few years.
Usually there is some kind of privilege or reward that comes with a certain number of posts, or a certain number of 'premium' posts, or other 'achievements'.
This site does not appear to have developed a gamification strategy, as it has no rewards (no matter how simple) for either the number of contributions, or the quality of them.
Yet the site keeps a count of the contributions in the form of both questions and answers, as well as the quality of contributions through the 'best answer' scheme.
Have to say, I don't really understand the thinking behind the site's efforts to keep users who offer good answers, and those who make many positive contributions.
But maybe that's a question for the Ed....