Webtrends Analytics 9 Adminstration Guide, November 2012
Webtrends limits tables in two ways: it limits analysis tables during analysis, and it limits report tables after web activity data has been analyzed, but before the report tables are written to the On Demand report database.
You can specify limits for both report and analysis tables for all reports (whether preconfigured or user-created).
During analysis, Webtrends uses an algorithm based on the age, frequency, and relevance of web activity data when deciding which records to include. Smart limiting means Webtrends collects the most significant data and aggregates records with low relevance.
However, there are some exceptions to smart limiting. For example, when reports use more than one dimension, only the second dimension uses smart limiting.