Kindle collection details (via TeleRead); I also learned yesterday that the Kindle iPad client already includes an option to see the most popular highlights in a book/information item; see “Viewing Popular Highlights” on this page for details, and this page to view popular highlights via a browser
If you store a lot of content on your Kindle, you can create collections to improve your organization. A collection is a category you create on your Kindle Home screen. You can then move your books and other reading material from the Home screen to the collections you create. Your Kindle will sort your content by collections after you create your first collection.
Kindle Home without Collections
Content Organized into Collections
More details on popular highlights (clipped from this page):