At the bottom of every topic's page we have designed list of users which are browsing this page now. When user is browsing topic his/her name should be shown in list at the bottom of the page. Other users should see list of all users which browsing topic now. List should be updated when page updating or user goes to next/previous page in paged topic. User have to be shown in list if he/she browse no matter which page of topic (number of pages may differs from user to user).