If you have a larger forum with numerous nodes this add-on may not be for you. You could still use it to just display who is viewing a thread.
This add-on keeps track and displays where members are viewing in categories, pages, forums, and threads. On forum home, you may choose to display the members avatar, username, or just the grand total of viewers (clicking the total will open an overlay that displays the members viewing that section of your forum). The data is displayed in a footer within each category, or under each section that does not have a parent category.
For categories, pages, forums, and threads a new row is inserted under the content that displays the viewing members avatar, username, or just the grand total. You may also choose to display members viewing these areas in a widget instead.