This seems like a natural extension of MIT's OCW which has been going for 10 years now. It may be influenced by Stanford's recent clases, but "reactionary" is a bit of a stretch. MIT has been giving away free classes online for a long time, adding credentials seems like an obvious extension of that, and one that would have likely happened regardless of what Stanford does.
I agree. And I agree it seems like a natural extension, however it's not the idea that's impressive, the action itself is impressive. There are a lot of forces that make this step incredibly difficult for universities, hence why it has taken so long.
Naturally they have to be very cautious of how they market and execute on any alternative credentialing system, both due to the new system being in competition with the traditional, and to ensure the branding will (or can) not tarnish their name.