My love for Hypercard is no secret, and I like the card metaphor, though I've no desire to see it applied to everything. I suspect we're going to see at least as many poor implementations as good ones.
But as I look around the mobile landscape, I see cards everywhere. Benedict Evans wrote a good post about this trend a few weeks ago. Google is pushing cards as a UI inside Android and their Google Now UI is the best example of that. Twitter has had cards inside of Tweets for several years now, although I wish they would display them by default in my timeline. The Facebook mobile UI looks like a series of cards, although you can’t really do anything with them, yet. And, of course, my favorite example are theKik Cards that are mini mobie web apps that run inside of Kik’s messenger. I’ve blogged about them a number of times here at AVC as Kik is a USV portfolio company.
It feels like the Hypercard metaphor has arrived as the atomic unit of content in mobile, both inside of native apps and, if Kik is going in the right direction (I think they are), as the default mobile web atomic unit (cards instead of pages).