This is "neat" - and squarespace actually looks like a great service, especially for someone who needs more than a simple blogger site, but less than custom hosting/etc.
BUT! what I'd love to see is what a "regular" user could do in 20 minutes. Learning the context of the app, where things are, what menu items do exactly which function you need- that's the learning curve people need to know about.
I mean, I could probably re-implement SvN in 20 minutes by skinning Wordpress- but that's because i use Wordpress all the time, and have done more skins for the thing than I care to recall.