By looking at the data on this report, you will be able to see how visits are coming in from your AdWords campaigns. If the campaign is bringing in good traffic, you may decide to increase the money you are spending on the campaign to bring in more. If the campaign is not bringing in good traffic, you may want to look at the Keyword Positions report--detailed next in this series--to determine if you need to increase your advertising or change your keywords.
Overall, the information here will help you in making sure your return on investment, otherwise known as ROI, is the best it can be.