The report, "Five Ways To Improve The ROI Of Your Behavioral Targeting Campaigns," suggests that nearly one-quarter of all interactive marketers use BT. That number will continue to grow as marketers strive to improve performance.

After slow growth for several years, BT has finally gained traction. In 2008, 24% of interactive marketers tapped the technology, compared with 16% in 2007. Forrester suggests the growth has been spurred on by a glut of ads making consumers numb to the message.

By far the biggest benefit marketers gain through companies such as Yahoo and AudienceScience focus on delivering a direct message to consumers most likely to pay attention, according to Forrester Research Analyst Emily Riley. But the problem in reaching the anticipated ROI resides in a lack of knowledge about an array of options.

Many online marketers have traditional marketing backgrounds, which have not allowed them an opportunity to explore the flexibility and the "scientific testing" that BT affords, Riley said. "Marketers may not even know how many options they have available," she said. "Marketers who work with agencies may not communicate their need for testing, and enter into a contract that makes any tweak to creative or targeting prohibitively costly or time-consuming."

While 75% of marketers who tap BT use Web site analytics to make more informed media buys, a lack of communication and trust between the client and ad network hinders the ability to maximize ROI.

It's important to clarify the objectives, messages and metrics. The campaigns are only as good as the marketer's ability to define a goal and measure metrics. To truly succeed, marketers must share objectives and metrics with business partners such as ad networks.

Riley suggests separating direct-response campaigns from brand campaigns. Then, set up a data-sharing system, for example, by distributing response metrics from your Web site or by implementing brand studies.

Marketers fail to share true objectives with clients, especially agencies wary of giving away too much information about a client's goals. Rather than protect interests, this secrecy sets the BT network up for failure because it will not have the ability to align the campaign's execution with the client's needs, according to the report.

Marketers also need to ask more questions, Riley said. For instance, marketers need to know how target groups are assembled; not all do. While one BT network might call a group of people "business travelers" because they read both business and travel sections of a few sites, another network might have a "business travelers" group based on real search behavior across search engines and travel sites.

The report also suggests that marketers should incorporate priority data in campaigns, share how the company will judge performance metrics with ad network partners, and make specific creative pieces for the BT campaign to send the correct message.