Some of the challenge comes from how we look at scale. We tend to think of it as something that only works well on identical widgets with identical interfaces.
I suspect - though cannot prove - that scale is actually more about how we direct information processing than about forcing everything to be identical. Processing things with massively parallel systems doesn't necessary mean that all the systems have to follow the same straight lines. (I know that's geometrically messy.)
Right now, our models for massively parallel are relatively simple applications that have massive numbers of users. That's the obvious place to start. As I watch the costs of these systems drop, though, I think we're going to see many more models emerge. That's a forecast, not a guarantee, but I definitely see opportunities there.
I'm also curious about how the spread of not only NoSQL but infinitely flexible tools like Git and GitHub change the way we view these kinds of processing. I suspect much more concrete papers than mine will be talking about the benefits of less regimented systems.
Thanks,
Simon