David Recordon has a very clever observation over on the O'Reilly blog about the Google App Engine potentially marginalizing both OpenSocial and Facebook Platform. I think he might be right. Long term, the goal of most App developers should not be to develop gadgets in containers, but rather to build first class applications on the ultimate platform of all, the Web.
With tools like Amazon Web-Services and Google App Engine reducing infrastructure and scale costs even further, an emerging data interoperability layer via DataPortability and an increasing desire to add social functionality to most apps and services, the future looks bright.
I look forward to the day when I can use my best-of-breed applications (such as Flickr for photos - and now video!, Twitter for status updates, Ma.gnolia for Bookmarks and Google Docs for document collaboration) all backed by my personal, universal address book. My personal social network.
Combine everyone's address book together and you get what you get is what Tim Berners-Lee calls the Giant Global Graph.
The opportunity for Myspace, Facebook and other large social networks? Continue to provide a simple user experience for the mainstream in the mean time, and evolve quickly into an Identity Provider and social hub of the future.