Currently Active Users & Moderators feature
 

There is a box on the bottom of some pages, where you can see users and moderators who are currently online.

1) Which pages does it display on; what is the logic?
2) (seems like) Lately it hasn't been showing up as often. Is that true, and if so why?

Thank you.

The "active users" box shows up at the bottom of each forum page (where you see the list of threads in that forum). However, it doesn't show up after you click on a specific thread. It let's you know how many members & guests are currently online in a forum, but not which specific thread they are reading.