The digital age has led to the advent of electronic collections with millions or even billions of items. This paper examines the types of interfaces that are emerging for large-scale collections, specifically addressing what a large collection looks like online and how it can be managed by users. In examining these questions, we propose some features that we feel are universally desirable in interfaces to collections. Overall, there appear to be two sets of features that help users effectively use and sort online content: tools to view, organize and navigate collections; and tools to customize and manage user-created sub-collections.