Facebook is facing some of the strongest headwinds it has ever faced since it was launched in Mark Zuckerberg’s dorm room in 2004.

For example, according to a recent report from Pew, nearly a quarter of Americans and half of millennials have deleted the Facebook app from their phones this year.

But while signs that its users are becoming less attached to Facebook generate catchy headlines, there are other shifts taking place that might be more important to marketers in the near-term.

Specifically, on its third-quarter earnings call on Monday, Zuckerberg told analysts and investors that sharing is moving away from Facebook’s News Feed to private channels such as Facebook Messenger and WhatsApp, which see tens of billions of messages exchanged between users each month.

This phenomenon isn’t new – it has been referred to as dark social for years – but it has clearly reached a level at which Facebook can no longer ignore its impact on its ad business.

In addition to messaging apps, a growing portion of the sharing activity in these channels involves Stories, a feature that allows users to post collections of photos and videos that are accessible for only 24 hours. Because they’re ephemeral, Stories might best be described as semi-private.

According to Zuckerberg, “People share more photos, videos, and links on WhatsApp and Messenger than they do on social networks.” And he thinks he knows the reason for this: “People feel more comfortable being themselves when their content is seen by smaller groups, and (the posts) don’t stick
around forever.”

The good news is that Zuckerberg effectively suggested that Facebook isn’t losing out as sharing behavior changes because it’s the leader in “most countries” thanks to its portfolio of apps.

But what’s good for Facebook isn’t necessarily good for marketers. Until now, Facebook’s ad offerings have focused on the company’s News Feed, where they can pay to boost the reach of the content they post to the social network. That has become increasingly important as Facebook has increasingly
prioritized content from users’ friends and family, reducing organic reach for businesses.

As sharing moves away from the News Feed altogether and its importance to consumers wanes, marketers face a potential double whammy.

Facebook’s biggest challenge?

Facebook has proven adept at finding ways to monetize its social network, and that has led many to believe that if any company is capable of capitalizing on the popularity of its apps, including Instagram, Messenger, and WhatsApp, it’s Facebook.

But because these apps are more intimate and largely facilitate one-to-one and one-to-few communications, Facebook might not be able to be as aggressive with its monetization efforts. For example, if it started stuffing private Messenger and WhatsApp conversations with ads, it would likely
face a backlash.

In fact, WhatsApp co-founder forfeited nearly a billion dollars worth of Facebook stock when he left the company over a disagreement about its plans to more aggressively monetize WhatsApp via advertising.

For now, Facebook appears to be focusing its efforts on semi-private sharing. For example, it has confirmed a new ad product for Instagram called Promote for Stories, which lets businesses on Instagram “boost” their Stories much like they can posts in the Facebook News Feed.

The big question for marketers is how the new ad offerings Facebook develops to address changes to sharing behavior will perform. The nature of this behavior is fundamentally different and as smart as the people at Facebook are, there is no guarantee that new ad offerings will perform the same way
News Feed-oriented offerings have. That could impact marketers that have been especially reliant on the News Feed and its associated ad formats.

While it’s too early to predict doom and gloom, the trend towards private sharing is well-established and Facebook itself is acknowledging this. If marketers take one thing away from this trend, it should be that content is arguably still king. People share content that is interesting and relevant in some way to their lives.

While ad offerings often allow marketers to put more eyeballs on content that is less-than-compelling can be effective to some extent, marketers should always be focused on how they can create content and associated experiences that consumers are genuinely interested in, and even willing to share with
the people in their lives.