Each has more than 100 Million credit cards on file to enable 1-click purchases of content, apps, and virtual goods.  When I compare doing anything involving payment on other platforms the experience is cumbersome to the point of being useless.  My 10-year old son had no trouble hijacking my Kindle, finding the store and getting a book for himself.  And that’s on the Kindle!  On his iPod touch he blew through the app budget we had set for the month within the first two days of having it.  It will be interesting to see who figures out how to catch up with Apple and Amazon and how they do it.  In the meantime, companies like Zong with their Zong Plus offering are trying to get there independently.  If they get to 10s of millions of linked credit cards, they will make a juicy acquisition target.