P.S. A small rule I want to add. You can post several times in a row if you want, but only posts that alternate between two members count.
For instance, I posted, then Dag posted, then I posted. That's three in a row. Then I posted again. It doesn't break the streak, but that extra post by me doesn't get counted as a part of the posts for the competition. So we are still at three until Dag posts again.