All the consumer data in the world is useless if marketers can't act on it, and Alliance Data wants to ensure it can do that across channels. The owner of data and email powerhouse Epsilon has agreed to spend $2.3 billion to buy digital-marketing-services firm Conversant in part to help ad clients target messages across devices, an especially complex thing to do in mobile.

For much of its 16-year-long life, Conversant was known as ValueClick, which stood as the last remaining large independent ad network before ad exchanges and programmatic buying began to dominate the display ad industry. The company changed its name to Conversant in February.

Though Conversant still offers legacy services for affiliate marketing, the firm's ability to tie individual devices together using an anonymized ID without cookies -- which don't operate in the mobile environment -- is crucial for Alliance. Alliance historically has focused more on personally-identifiable offline data than connecting anonymized digital IDs, a necessity for mobile targeting.

"As it pertains to mobile, what they bring to the table is quite important," said Epsilon CEO Bryan Kennedy in an interview with Ad Age. Though he acknowledged Alliance was attracted to Conversant in part for its ad technology, "more important than that, it's their cross-channel" capabilities. ValueClick acquired one of the first mobile ad networks, Greystripe in 2011.

"For us it was less about, 'Hey we just want to be another brand in ad tech,' and more about how do we solve this [cross-channel] problem for clients," he said.

Conversant will live as part of Epsilon, said Mr. Kennedy. "They essentially become the digital-media business for Epsilon," he said. Both firms have strengths in display advertising, and the combination should afford them greater scale. Conversant's mobile and video ad products also will complement Epsilon's Agility Harmony system for targeted digital communications.

The companies have potentially synchronous offerings for retailers, suggested Mr. Kennedy. Alliance Data operates a private-label credit card service for retailers, while Conversant has a focus on retailers through Dotomi, the retailer-centric dynamic display ad business it bought in 2011 and linked with its other businesses including Greystripe and its Commission Junction affiliate network, another retail-aimed service.

"Conversant has a strong footprint in the retail industry, particularly with Dotomi," said Mr. Kennedy, noting that packaging that with its white label credit card service, "is a very logical place to go."

As part of its Commission Junction business -- now known simply as CJ -- Conversant still offers lead-generation services. In 2008 ValueClick settled with the Federal Trade Commission, agreeing to pay $2.9 million to the agency as a result of its investigation into lead-generation ad practices alleged to have violated the CAN-SPAM and FTC Acts. The FTC claimed the company duped people into providing contact information in exchange for chances to win prizes. Mr. Kennedy declined to comment regarding the settlement.

Don't expect true backend tech integration between Alliance and Conversant just yet. "In 2015 Conversant will operate essentially as it does today and our focus will be on cross-selling," said Mr. Kennedy. Figuring out how to connect the platforms will come later, he said.

Conversant CEO John Giuliani, formerly chief of Dotomi, will stay on in his current role, and help guide Epsilon's digital strategy.

"He and I are good friends," said Mr. Kennedy of Mr. Giuliani. "We will really be looking to John to lead the charge" to determine the direction of Epsilon's digital path, he added.

No other "significant changes" are expected for either firm, he said.