A contract specific limit exists, that restricts the number of trackable expressions per dimension (e.g. page, event, ad media, ...). For example: How many different pages can be tracked in total?
Therefore, Webtrekk provides the possibility to group different expressions. For example: All pages, that have been accessed only once.
The expressions, that were grouped like this, are depicted as "webtrekk_aggregated". In our example all Page Impressions of the grouped pages would be assigned to the new page "webtrekk_aggregated".
Please refer to the Webtrekk Support for activating the data cleansing.