After a year of working on the format, Pinterest is now launching a full beta of Story Pins as the company tries to tap into the social Stories trend but with a platform-unique approach.
As Pinterest explains

Story Pins is an entirely new type of Pin and publishing possibility that will enable creators to tell dynamic and visual stories by using video, voiceover, and image and text overlay. We're making it easier for creatives eager to share their talent, passions, and creativity to flow back into Pinterest directly from their imaginations instead of having to set up a website. To a Pinner, this would mean the ideas within a Pin will be more engaging and actionable.

As you can see in the screenshots above, the Story Pins format is the same as other Stories options; it provides a full screen swipe feed of frames.

The difference here is that they are contained within a Pin, rather than a separate feed of Pinterest Stories, whereas Story Pins also don't disappear after 24 hours.

Story Pins will be discoverable over time and can be saved to boards for later. They also will be distributed across the home feed, search results, and places such as the Today tab and therefore will benefit from the visual discovery engine that matches new ideas with people who have the relevant interests and tastes.
So it's kind of like Stories in spirit, but for business purposes it's not the same. Still it should give you a way to recreate the Stories experience inside of Pinterest-which, giving the popularity of the Stories format, could be a good way to connect with your on-platform audience.

The company is introducing Story Pins-a new way to create and share Stories-for selected creators in the US, with availability opening up to other regions in the coming months. Interested creators can sign up here to learn more about Story Pins.

To help creators build their audience, the platform is improving creator profiles with a new display format along with updated contact options.

"Pinners can also respond to the ideas found from their favorite creators with different positive responses like "Great idea," "Love," "Wow," and "Thanks" to provide a great response to creators."
These responses aren't entirely new; Pinterest has been testing them for a while, and they have been available to most users in some Surfaces. However, they will now be more widely available on posts and create another medium by which to interact with Pin content.

Pinterest is also introducing a new Engagement tab for creators, through which they will be able to manage their Pin activity all in one place.
The company plans to roll out several new features, including an analytics dashboard; the redesign will depict a rich view of how content is performing.
And yet, at the same time, this seems to be just a little bit strange to place Stories on each of these platforms, for the data shows that Stories has become an essential content format, like the news feed did before it. So obviously, then, all these platforms should follow in line with their audience behavior and offer more options so people can connect in the ways they are becoming habitually accustomed.