At the heart of each card is its key asset. It may be a photo, a short description of a shared article, an embedded video or a product description but more and more, you’ll find it’s accompanied by a new call to action button.

We’ve already seen these buttons allow sign up to newsletters (easy when Twitter has your email address already) but in another upcoming example, Twitter Cards can provide a “call” button, creating an immediate way to contact customer support or nurture incoming enquiries about your business.

That move also makes sense given many users have already registered a mobile number on their profile.

But the next phase gets serious. Square is apparently in talks to introduce the first ‘buy’ buttons directly in Cards, bringing impulse purchases to a new level of convenience.

Whatever function you can already achieve on the web, Twitter will be working with partners to include it as an option on Cards. And these cards can be curated into selections and embedded anywhere.

This is part of the atomisation currently sweeping through the whole web, accelerated by the ubiquity of mobile.

As that happens, the question of authorship becomes more important. A new Twitter profile design has already leaked that emphasises the most popular recent Cards from that user and give them an opportunity to curate them by hand. And wouldn’t a Card look nicer on a smartwatch than a web page?

Furthermore, because Twitter Cards can be based on existing metadata of websites, they can be simply generated at scale. For example, Amazon can immediately translate any product listing into an accompanying Card.

At that stage, what’s to stop you making a page of the cards, searching by its metadata and cutting out the middle man? Or creating a simple shopfront by creating a search filter of friends’ “Buy” cards?

So let’s ask again: what’s the difference between a news site and the collection of its stories’ Twitter Cards? The answer is they’re easier to digest, share and interact with than almost any other format so far.

So where does this leave us? Cards are the mobile language of the web. They’re springing up everywhere from Google Now to iOS and beyond.

But Twitter is in a unique position to encapsulate these small calls to action in the simplest, most platform-agnostic and shareable way.

As the web breaks down into smaller and smaller pieces, and wearables are simplifying hardware alongside it, Twitter Cards are in the right place at the right time to create a new kind of web.