As suggested, posts only within the two ish week period are counted towards activity. Time spent online != Activity. It can be confusing, but basically the more you post, the more likely you are to hit these periods which give activity, since you only need to post once inside of them to gain the 14 activity or potential activity since you would still need equal or more posts than the potential activity for it to be displayed.
Right, so basically as I've always understood it, for your first 14 days on the forum you get 1 activity point added per day if you post at least once a day. After that, activity starts increasing by 14 points per 14 days but only if you post once during that 14 day period--and the period begins on Tuesday/Wednesday depending on your time zone. Does that make it any clearer, OP? I haven't looked at your profile, but you should be getting up to an activity of 28 either today or next Wednesday. Either way, it's going to happen and you don't need to worry about it.
