I'm looking for a module that, given a page URL, returns the list of users who are currently viewing it. The list should be dynamically refreshing to show page view activity in real-time.
Is there a module for that?
Check the viewers module ( https://drupal.org/project/viewers ):
As stated it won't provide you the functionality of dynamically refreshing to show page view activity in real-time, but you can modify it through the custom code by refreshing the block after a required interval of time or else can try the block refresh module ( https://drupal.org/project/block_refresh ):