Webtrends Analytics 9 Adminstration Guide, November 2012
With Webtrends v7.0 and higher, WT.mc_id replaces WT.mc_n and WT.mc_t for marketing campaign reporting.
Identifies a specific marketing campaign. Pass this query parameter to pages that you want to associate with a specific campaign. You can specify a numeric or string value.
This parameter identifies that the page is associated with a particular ad. This parameter is read and stored into Visitor History, and written back on the URL as WT.vr.rac.
|Valid Value:||Alphanumeric string|