ok, I will address this.
After a few weeks of registration you are given a message at the top of the forums. It is only showes for people that have not made at least one post. The text is below (from my testuser account):
Hi testuser, You are member of Eastvale Residents Forums for a 24 days now but haven't posted anything yet and will be considered an inactive user after 30 days from registration without at least one post. Please post soon and contribute to the community discussions. It's FUN!! 
The intention is just to encourage people to post at least once within the first 30 days. After their first post, the message goes away. The inactive part means it will be reflected in the active/inactive stats at the bottom of the front page. That stat tells me the % of active/inactive participation the board gets. It does not mean you will be booted or anything. It's just a friendly nudge to get people to participate at least one time.
After they post one time, they are more likely to post again.
