It's been widely reported that Ning will join Google and others this Thursday for an announcement of a new set of Open APIs for applications to that can be embedded in many social networks.
I have added to this discussion on my blog, but wanted to note here that when this goes live on Ning it will be supported across all Ning networks with appropriate controls for network creators to disable, enable, etc.
The OpenSocial apps will be similar in functionality to Facebook apps, so it will be another great way of adding new stuff to Ning networks. We plan to aggressively support these APIs, but we will
also continue to work on improving the developer experience on Ning itself. That is, OpenSocial will be another option that developers will have to add functionality to Ning networks, in no way this changes our plans to provide better tools to write, manage, and merge code that runs on the platform, and to continue improving and expanding our REST and PHP APIs as well.
If you have any questions, please post them here -- we will also have more details (and videos!) on Thursday.