Activity = In simplest, Maximum of 1 POST per day is counted as ACTIVITY.
Regardless of how many post you made per day, the activity would still only 1 per day.
And Activity update is every 2 weeks which is equivalent to = 14 activity/post.
No, read the post above yours. If you can't understand the engrish, it means that you get 14 activity per 2 weeks(starting and ending on tuesday, a thread had the exact details), which you can "use" in a single day/hour/min. .