In this report, you can see how many visits had a certain total duration. Initially, the report is shown as a tag cloud, more common durations are displayed in a larger font.
Please note, that you can view the report in other ways than as a tag cloud. Use the controls at the bottom of the report to do so.

Report generated 21s ago
7-10 min 31-60s 30+ min 15-30 min 10-15 min 2-4 min 4-7 min 1-2 min 0-10s 11-30s