Just finished viewing this movie about Google's OpenSocial initiative. Here is a quick quote to let you know what is this all about:
"OpenSocial provides a common set of APIs for social applications across multiple websites. With standard JavaScript and HTML, developers can create apps that access a social network's friends and update feeds."
There are many websites implementing OpenSocial, including Engage.com, Friendster, hi5, Hyves, imeem, LinkedIn, MySpace, Ning, Oracle, orkut, Plaxo, Salesforce.com, Six Apart, Tianji, Viadeo, and XING. And I am expecting that the list will grow since this is Google after all.
Open-Source Opportunities
OpenSocial.NET (or even LinQ to OpenSocial!):
.NET Wrapper for all server side functionalities in OpenSocial.
OpenSocial jQuery: client side?
This could be cool.
Facebook Wrapper:
IMHO, Facebook won't adopt this standard until sometime because it already rolled out it's own platform a looong time ago. So there should be some kind of wrapper around opensocial to map facebook APIs to make creating apps that work even in facebook possible through opensocial.