There are so many people out there right know who dont know how the activity system works
You are the one who doesnt know the activity system works
These account cant be potential full members or other ranks because they are old.
Yes they could, providing you posted atleast once in 2 weeks period
The forum ONLY counts max 14 activity every 2 weeks and these periods are not stackable
It is stackable because your activity cant go higher than your posts , by posting atleast once in 2 weeks period, you are indeed stacking them up
You're right in saying that accounts can't gain activity only because of their age, but rather, are restricted in the activity they can gain by the 2 week periods; but, as far as I know, the periods are "stackable", in the sense that, if you have posted only a couple of times (< 14 posts) in every 2 week period since the account was created, you can later collect the missing activity you didn't gain then - or, as you put it, you can later post 100 times to collect 100 activity points instantly. Of course, all this requires caskey4521 to have had the foresight of making all those posts throughout the periods - if he didn't, then the activity is lost forever.
Did the rules change, or did I never really understand this?
You understand it well completely, and it is how the system works, providing you posted atleast once 2 weeks period you will be eligible for 14 activity points
I wondered how that worked. thanks.
Is there any other things we need to know about activity rating?
for more info about activity , heads up and read it up here
https://bitcointalksearch.org/topic/forum-rankspositionsbadges-what-do-those-shiny-coins-under-my-name-mean-178608