Topic views are a very useful bbPress feature allowing you to list topics outside the forums based on different criteria or search parameters: activity, freshness… bbPress has few default views, but it also allows adding of new views. It is important to know that Topic Views are implemented by the bbPress, and GD bbPress Toolbox Pro or GD bbPress Tools Free plugin can only register new views, they can’t do much else related to views.
Default bbPress topic views are:
Most popular topics: this will list topics by most replies.
Topics with no replies: this will list topics with no replies.
Views work on all topics, regardless of their forum, and the list displayed will contain only topics ordered by the view default criteria (they don’t have easy options to reorder topics or filter by forum).