Tiles open upon tap to reveal detailed contextual information. (Swiping them reveals actions to clear or snooze the notification.) They can be dynamic, changing based on conditions like time of the day, location, or what the user is doing at the time. And because app makers have flexibility, they can design and develop their tiles that offer information separate from what's in their actual app.
Added bonus: The app category list displays the number of notifications in each category.
Apple's iTunes Store is nearing 50 billion ? billion! ? downloads. Here are the most-downloaded tablet apps ever.