Image source: Snapchat.

In just four short years, vanishing-video pioneer Snapchat has built one of the most successful social-media platforms. Its service is unique, and it's the only social network with privacy at its epicenter.

This seemingly contradictory nature has allowed Snapchat to emerge as the most formidable challenger to social-media titans Facebook (META -1.36%) and Twitter (TWTR). So why would Snapchat come up with a feature that seemingly undoes its defining feature?

Let's take a look at Memories.

What is Snapchat's new Memories feature?

According to its press release, Snapchat's new Memories acts as an alternative to your smartphone's camera roll. The new feature allows users to save, search, add geofilters or captions, and even post previously recorded photos and videos into your current story, all within the Snapchat app.

To solve the potential confusion from mixing the past with the present, older images and videos added into current individual messages or posted into Stories will feature a white frame and time stamp. Also of note, in a nod to the service's more lewd uses, Snapchat's Memories also allows users to save possibly offensive or explicit images and videos into a password-protected "My Eyes Only" area.

Here's the promotional video Snapchat released as part of the press release announcing Memories.

Users were already able to save their own images and videos from Snapchat into smartphone camera rolls. However, building this new feature into the service itself represents one of the most significant shifts in the company's history, and a host of companies across the technology industry are likely to feel the impact.

Cui bono? 

Allowing pictures and videos to lives beyond their original 24-hour lifespan changes the basic premise of the platform, yet it seems Memories strikes an appropriate balance in doing so. I don't think it will cause much attrition. As Snapchat gains in popularity, users will want to use the service as the primary tool to document their lives, and the ability to share experiences with friends retroactively is a key aspect of that desire.

So it's clear that Snapchat stands to benefit. And in terms of how introducing Memories skews the competitive balance in the social-media space, it's a net negative for Facebook, Twitter, Facebook-owned Instagram, and the like. Even without Memories, Snapchat may already be having an effect on its older rivals. For example, sharing of user-generated content has reportedly declined at Facebook, a trend that's said to have prompted Facebook's recent algorithm changes. That shift may not be all due to Snapchat, but increasing engagement on the forum would suggest that people aren't spending as much time on other social networks.

However, Facebook and Twitter aren't the only tech companies that may suffer as the result of Memories' public rollout.

Image source: Snapchat.

Snapchat's move to create a space for users to store their Snaps within the app could also damage mobile-OS providers Apple (AAPL 0.33%) and Alphabet (GOOG 2.51%) (GOOGL 2.37%).  With the ability to store, sort, and search images within the app, Snapchat has created a powerful alternative to the default camera rolls that live on Apple's iOS and Alphabet's Android platforms.

Much like Apple's and Alphabet's increasing interest in on-demand streaming, the OS providers don't necessarily care about these specific functionalities as profit centers. That's part of why it's a no-brainer for Apple to lose money to counter Spotify in streaming, a horrible business if there ever was one. Like listening to music, taking and sharing images is a core aspect of the smartphone experience. So by creating a viable, and arguably better, place for users to store their images, Apple's and Alphabet's critical mobile ecosystems become at least slightly less sticky.

Ultimately, Memories alone won't have a meaningful impact on any of these big industry names. However, it does serve as the latest example of the increasing clout Snapchat exercises throughout the tech industry, one that only figures to increase as the service's popularity continues to grow.