A roll-up of traffic sources in the Acquisition reports that groups several marketing activities together. Channel groupings allow you to view and compare aggregated metrics by channel name, as well as individual traffic source, medium, or campaign name.
In the Acquisition section's Overview and Channels reports, you can see your data organized according to the Default Channel Grouping, a rule-based grouping of the most common sources of traffic, like Paid Search and Direct. This allows you to quickly check the performance of each of your traffic channels.
