Well indeed it was mentioned so many times ...
but I will make it clear for you in easiest way.
after each two weeks your activity can go + 14 max.
If you will post 14 posts in 2 weeks period you will get +14.
If you will post 1 post per two weeks you will get +1.
If you will post 100 posts in two weeks your actv will go up +14
but if you will post none in next two weeks you will get +0.
That's it.