The document discusses six trends in collection development for the 21st century: 1) E-volution and the rise of ebooks and e-readers, 2) Recommending academic and productivity apps for mobile devices, 3) Implementing personal digital assistants (PDAs), 4) Flipping physical collections and shelving, 5) Reconsidering Dewey and subject classifications, and 6) Marketing collections outside of the physical library walls through websites and online resources.