When you click the Active Topic's option on the menu bar a drop down menu apears that allows you to select 3 options. When you select one of those options it will give you a list of links within the time range you've specified (Past 24 hours | Past 48 hours | Past 7 days).
The Active Topics are a list active threads within your selected time frame. The active posts is a list of all postings that took place during that time frame, and the Unanswered Posts is a list of all posts that have had no replies to them within that space of time.
“Life’s journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy ____…! What a ride!’” ~Hunter S. Thompson