The widget displays 'All content', i.e. when I select Yes for Discussions, Documents, Blogs, Ideas, etc But does not display data when I restrict to Only 1 content type (Document, Discussion or Blog post), stating
Once people begin collaborating, you'll see the most popular items across the community. Start collaborating with others and your content might become the first popular item.
I event tried to reduce the 'Number of Results' to see if that would be a limiting factor but No.