The exit page statistics are looked at to consider what makes a person leave the site. If the exit page is something other than the page after an order is made or the last page of a list of informational material on a given subject then analytical tools will pick up the rates at which users drop off on specific pages.
If a high amount of users use the same exit page that is not considered the page the web site would want the user to view last, tweaking to the page will be done to make it more appealing. This should make the page less likely to be exited from. The analytical reporting will note whether the changes to the page result in less exits and continual tweaking will be done until the exits drop off or decrease.