If you have important or recommended topics that your users might find useful, the custom Topics widget can be used to focus attention to those topics and make users aware of them. For example, you might configure the custom Topics widget to only show specific topics that you think members of a certain community members might like to see or that are essential for them to see, and then add it to the homepage of a that community so that those users can see them each time those topics as soon as they land on the community.
...