You can now buy iTunes gifts from within Facebook's gift system. iTunes gifts in Facebook are available for $10, $15, $25, or $50, and can be used to buy videos, music, apps, and more. Facebook says:
Starting today with Facebook Gifts, you can instantly gift your friends iTunes digital gifts and recommend albums, movies, games, apps, and more available on the iTunes Store.
Search for a specific song or album to recommend, or let your friend decide. iTunes digital gifts are available for $10, $15, $25, or $50.
This follows Apple making iBooks discoverable in Flipboard, and it's quite a strategic change for Apple. Previously, if you wanted Apple's digital content, you went to Apple. Even their grand, and ultimately ill-fated social experiment, Ping, lived in iTunes. Now, post-Ping, Apple continues to outsource social, and Apple starting to come to you.
Sure, if you're already in iOS or OS X, you can use Twitter and Facebook integration to share, but if you're not, if you're in Flipboard and Facebook (and presumably other places, eventually), Apple's content will be there for you to "discover".
Amazon gets a cut of iTunes revenue, Apple gets a much larger visible footprint.