Webtrends Analytics 9 Adminstration Guide, November 2012
If you use Webtrends query parameters to track content groups, you can use Visitor History to associate visitor activity to content groups viewed in a previous visit.
Webtrends provides the preconfigured Content Groups of Interest custom report that shows how each content group performs for new visitors and for visitors in each time period. Keep in mind that because Visitor History tracks a maximum of 10 content groups for each unique visitor analyzed for a profile, and visitors are likely to interact with many content groups in the course of a year, this data is most insightful for smaller time frames, such as daily and weekly.
When you enable content group tracking in Visitor History, Webtrends generates Content of Interest Visitor parameters that track content group data for each unique visitor. The Content of Interest Visitor parameters provide data for content of interest measures. Do not use content of interest measures with dimensions other than the Content Groups of Interest dimension.