Single sign-on / alternative authentication has been a highly desired feature from Ning in the past, and will potentially allow institutions and organizations with existing membership bases to incorporate access to Ning into their existing services.  It seems like there will be a couple of other somewhat intriguing options here as well, including logging in using Facebook or Twitter authentication.  What's not entirely clear in the material--or, according to John, to Ning yet--is if these features will be included as part of the Pro service or an extra fee.  

If you don't pay even the minimal amount, currently your network and all its content will disappear 30 days after the July shift.  While Ning will likely provide some capability to get a network back within some limited period of time, the idea that created content is not "grandfathered in" and retained even in some format feels bad.  I'm not sure how bad it actually is, but I'm hoping they reconsider this in some way and while not allowing those networks be functional, it would be nice to have the content statically available for posterity.  I'm also thinking about all the networks that will be created in the future--the idea that if for some reason you stop paying Ning all of the contributions "disappear forever" will be a mental and real roadblock to using the service.

The "major educational company" that has no name could be good or bad.  I'm assured it will be good, but I can imagine more than one large educational company whose providing Ning Mini networks for free would be looked upon with suspicion.  What's also not spelled out is what kind of control that company will have, their ability to market or message to the creators and members of the networks, and if there will be any advertising by that company on the networks.