One of the fluffier bits to come out of the Apple event today was a new app called Cards. It lets you make greeting cards on an iPhone, and Apple will ship it anywhere in the U.S. for $2.99, or $4.99 outside of the U.S. Push notifications are included in the app, so you know when the USPS has made the delivery.
Apple has been known to get a little fun with their apps, such as with Photo Booth for the iPad 2, but the greeting card thing seems like a bit of a stretch for Apple. Printing and shipping and all that continuous effort seems like a lot to dedicate within a company that should be spending its time making gadgets. Besides, there are already services like Postagram that do this kind of thing for way cheaper.
In any case, if this kind of thing is your bag, Cards for iPhone will be available starting October 12 in the App Store, along with the rest of iOS 5.