Smart folders are collections of groups and folders that give you hierarchical search capabilities. Here’s an example of a smart folder named Literature, which contains nested static groups, smart folders, and smart groups.
Term Lists in the List View (as below) or in a separate window keep track of every author, editor, keyword, journal, or items from almost any other field. Select one or more terms to instantly retrieve all the corresponding references. Add terms to one or more references with a simple drag and drop or contextual menu. “Pin” terms and use the text filter to drill down through your terms to find just what you need.
The number of degrees of freedom is, well, liberating.