I really respect GP's opinions on a lot of SaaS-related issues, but this one might be pushing my boundaries a little bit. GP is starting to confuse a rich client experience sitting on some "free" cloud storage as an S+S story. I don't know about this. It's a very small step from storing a document on a file server somewhere, anywhere. The only difference is that the "save" API used is slightly different.
Now, if something happened to GP's document once it was stored, or even better, while he was editing it. And that something happened because GP had signed up for a cloud-based service that added value to the client, then I'd have to say have another sip. But, this is not what I think of when I think of S+S (disclosure: I'm not part of the DPE organization that truly believes in S+S and I'm no longer part of the MBS organization that wanted to believe in S+S).
The "light-up" scenario just doesn't cut it for me. I want SaaS - either the stuff runs in the cloud and that's my primary interaction point, or the cloud is completely indispensible like in IM, or we finally start building service-oriented applications where stuff just runs and the fabric figures out where things happen. But, saving an Office document to a SharePoint site? Not so SaaS.