so the "activity" part goes according to logins or posts? Just wondering since "activity" and "posts" are separate when I log in... I assume only I can see the posts since I cant see other members...
The activity is related to the posts but unlike posts and as explained on the OP, it will only increase by a maximum of 14 points per 2 weeks period.
If you want to enable seeing posts for everyone inside threads, you can go to your Profile => Forum Profile Information => Show post count by posts (Tick this option).