We added a system to earn points by posting interesting messages, but that plugin had serious memory issues and the forum became very very slow. we had to remove it.
we might add it again in the future, but it will require a lot of work (if not a full re-coding) to make it possible.
for now, it's only the medals (some people seems to care about it) which are only based on post count.
there are users with power (contributors, reporters) which get this status by being helpful and contributing to the forum's life. posting interesting news, writing game's review, etc.
there are also users who help the moderators by reporting posts which contains illegal files, or users insulting each others, trolls, spam, etc.
there are contributors as developers or hackers, people contributing with new releases and knowledge in the scene.
so there are a lot of way to "rankup", but it's not specifically based on the number of action you did. it's more like being noticed by other users.
some users are well known, for being helpful or being trolls, their own choice