This window shows website traffic comparison between the previous and the current period. You can switch between visits, page views or unique visitors. You can change the period by selecting a new period on the dashboard toolbar.
If the period is day, you can see the comparison between the best and the current day.
The total number of visitors that came to your site. A visit is considered to end when a visitor leaves your site, or when he has spent more than x minutes on it. You can change the value of x by editing your account information and entering the desired value in the "new visit after" field.
The total number of page impressions.
How many different people have visited your site in a specific period.