The report and metric names used in Google Analytics are generally straightforward, but some require further description. You can hover over metric names in any report to display concise and helpful popup descriptions. (This type of popup description is often referred to as “contextual” help, since it provides assistance directly within the context of the interface as opposed to a standalone help system.)
The popup descriptions can be particularly useful in reports such as Ecommerce, AdWords, and Site Search, all of which display specialized metrics.
So the next time you’re wondering how AdWords ROI is calculated, how Ecommerce Quantity and Unique Purchases differ, or what Search Depth means, hover for some quick assistance.