The problem is, once you make the definition more specific, like this, the idea that "cards are the future" starts looking much more dubious - I'm not sure any

The problem is, once you make the definition more specific, like this, the idea that "cards are the future" starts looking much more dubious - I'm not sure any of the examples of supposed "cards" in the post fit this definition. Maybe Twitter and Google Now have enough of these elements to count, just about, but I don't see how Pinterest or Spotify do. "Here's some websites that put information in boxes" is plausible but not very interesting; "cards are the future of the web" is more interesting, but doesn't really have any evidence to support it.