The approaching end of third-party cookies is top-of-mind for marketers, many of whom are wondering how they can pivot toward getting more first-party data.

How brands will make the most of that first-party data will redefine online marketing. The effort begins with gaining not only the attention of customers but also their trust—their belief that your brand's content, products, and experience are worth a piece of their privacy.

Without the tracking cookies and targeted advertising that have become so common across the Internet over the years, marketers will be exploring alternative strategies for collecting data and connecting with customers. One strategy will stand out: the creation of compelling digital experiences that encourage audiences to willingly share their data in return for the ability to engage with the content.

Brands need creative online content that strikes an emotional chord, that tells a story, that moves beyond transactional thinking to instead embrace the human experience. The brands that do that well will gain a new trove of valuable buyer information while also respecting customer privacy. Those that fail will be floundering amid the new digital marketing reality.

First-Party Data, Please

In hindsight, brands should have seen the "Cookiepocalypse" looming. They gorged on third-party cookies so greedily that their gluttonous cross-site ad targeting started freaking everyone out—privacy advocates, of course, but also typical consumers who were spooked about everyone on the Internet knowing everywhere they'd been.

So, Apple and Google are moving to restore a degree of online privacy by eliminating brands' ability to track user behavior across multiple websites—the end of third-party cookies.

What will emerge from such a monumental change for digital advertising and marketing is yet to become clear, but the value of first-party data—particularly the information customers choose to give you—will be front and center. Without it, marketing troubles lie ahead.

The publishing industry will have to replace up to $10 billion in ad revenue with a combination of first-party data, updated contextual targeting, and probabilistic audience modeling, a recent McKinsey analysis suggested.

How will brands get that first-party data? They will have to ask website visitors through required registrations (an email address) or an explicit request for personal information for access.

"After the loss of third-party cookies and identifiers," the McKinsey report said, "advertisers and publishers will find that the value of direct engagement with consumers will further increase. To create consumer connections, advertisers and publishers should create experiences that consumers consider worthwhile."