For more than a year now, marketing experts and analysts have urged marketers to migrate and harness customer data across platforms and across the enterprise. Doing so, they say, brings together a rich mix of declared and inferred customer preferences and affinities, enabling marketers to craft more meaningful messaging. But the enormity of such a task leaves many marketers at a loss for where to begin. Nevertheless, in a crowded marketplace increasingly demanding relevance, such integration is vital to improving customer loyalty, accelerating the conversion process and driving measurable increases in marketing ROI.

So where does one begin? While email marketers agree that more relevant communications are needed to spur ROI to new levels, most still don't use Web-site clickstream data to target campaigns. Why? Lack of resources and the difficulty of integrating between email and Web analytics applications are most often cited. However, a wave of newly-formed partnerships between email service providers and Web-site measurement firms, and an ability to start small, means there's never been a better time than now. In addition, marketers who lag behind risk being overtaken by their competitors: In a May 2005 study, JupiterResearch reported that 41 percent of email marketers said they planned to begin using Web-site behavioral clickstream data as an email targeting tactic sometime between May 2005-2007.