That is a really interesting article on the Up and Downsides of adopting a visual metaphor of "the Card". It reflects some of the issues that came up in
Is TiddlyWiki A Card Index System?One of the things that stands out is that designers often use the "Card" (ideally "cards" of equal size and proportion) to handle "discrete chunks",
only to find that the chunks are not that discrete ... so add on linkage, or distort card sizes to be unequal.
I think its definitely the case that the "Card Index" metaphor has great appeal, both logistically and visually, but I think its equally important to see how often it is quickly breached. And when its breached, visually it doesn't really work so well.
The question is: WHEN is its usage really of benefit?
To give an example of usage that makes sense: Say you were Tweeting via TiddlyWiki ... well that does makes sense because every Tweet IS an inherent fragment of an absolute determined, invariable available length (280 characters). The question of linkage to an expansion of the Tweet does not arise. And there is a clear conceptual division between what the Tweet natively is and anything it references / links to.
Not much is so tight as Twitter natively is. Mostly "Cards" tend to end up invoking "pages". Perhaps an exception is when the "card" is centrally an IMAGE. There the heft of the visual meaning subsides enough to resist clicking through to the next level?
Just thoughts
Josiah