The Popular Articles list that appears on the Homepage is designed to show which are the most popular, or most visited articles that people have viewed.
Seeing a list of Popular articles is often helpful to see what other people are reading, since this may also be of interest to you, so having this list that shows the most popular articles is a convenient way to access those articles.
Popular articles will only be shown in this list if they are marked as "Published" and also only listed if the current user is allowed to view the article, based on User Groups settings they have been assigned match the Groups assigned to the article's category.
This list will automatically populate as articles start to receive visitors. The maximum number of articles appearing in this list is also controlled by Admin Settings, including an option to specify this list is not shown, if desired.
