• by Joe Mandese  @mp_joemandese, April 28, 2014

With Madison Avenue accelerating its shift from “media-buying” to “audience-buying,” one of the biggest audience platforms of all -- Facebook -- reportedly will unveil its own audience-based ad network on Wednesday during its so-called F8 developers conference. The shift may seem like semantics, but it represents a fundamental change in the way advertisers and agencies target audiences and spend their ad budgets to reach them.

Ad networks are far from new, but Facebook’s new network -- dubbed FAN, for the Facebook Audience Network, according to AOL’s TechCrunch -- will bring phenomenal scale and precision data for targeting consumers to Madison Avenue’s audience traders.

During F8, Facebook is expected to call on its publishing and mobile app developer partners to join the network, which will enable them to target registered Facebook users wherever they go. It’s expected that the mobile ad network will utilize most standard mobile units, including banners and interstitials.

The FAN name may seems obvious to Facebook’s development community, but it’s likely to rile executives at News Corp., and The Rubicon Project, which acquired the Fox Audience Network, or FAN, as part of an equity deal with News Corp. in 2010.

Whatever they’re called, audience networks are a rapidly growing part of Madison Avenue’s business, and are part of a broader shift from buying media as a proxy to reach consumers to buying direct reach among consumers themselves while they’re using media.

Facebook’s challenge will be convincing independent publishers to contribute their audience reach into FAN, effectively shifting “monetization” of their users from their own direct sales organizations to Facebook’s.

While ad networks are not new -- AOL’s Advertising.com is the granddaddy -- FAN is part of a a new breed of mega-scale ad networks leveraging their humongous reach and registered user base. The move could further crowd out and marginalize a rapidly growing cottage industry of independent vertical mobile ad networks such as AdMob, MoPub and Tapjoy, many of whom aggregate reach by affiliating with mobile app developers too.