Im suggesting to bring back the old type of ranking system but this time the posts of every members of the forum should be monitored first before it can be converted into "ACTIVITY"
Woah, this is way impossible. There are millions (thousands?) of members here and million of posts are being generated every day and monitoring every one of their posts is a suicide and just a waste of time. How can you come up to idea like this? By just forecasting the possible outcome of your idea well its a total waste of time, really. Moderators can't even stand to monitor and ban other spammers without concerned member's reports and how do you think that they can monitor such millions of posts? Our Moderators are humans, not robots who can can execute millions of codes in just an instant.
All those "bounty reports and related to it, those non-sense one/two liners, off-topics, super poor english grammar and so on and so forth will be counted as POSTS but it wont be included and counted as an ACTIVITY
Actually, activity is not important to spammers and twitbook hunters. As long as they can post links of their daily reports then they have no problem at all. So even if this one is applied, nothing will change.