Webtrends Analytics 9 Adminstration Guide, November 2012
When you specify Domain Name, SmartSource Site ID, or URL Query Parameter for splitting, Webtrends Analytics 9 automatically splits your web activity data into subsets, creates child profiles based on it, and, when you analyze the profile, creates reports for each child profile.
If you are using Full-Featured Analysis, you can also split data by specifying URLs. Splitting by URL is helpful in situations where you're segmenting your customers by directory. For example, your URLs may use a structure such as www.hostname.com/~customername. However, Webtrends does not support auto-discovery of new Child profiles based on URL. Splitting by URL requires you to manually configure each Child profile, specifying the URL strings to parse for in the log file.