You probably accept various payment methods on your store: Credit Cards, AMEX, Paypal, Cash on Delivery, Bank wire, etc., and you want to get a quick overview of how your revenue is distributed across these payment methods.

You can easily do that by choosing Revenue breakdown by Payment methods, in the Revenue Breakdown tab.

If you want to go one step further and see the traffic source of clients that use only credit cards, click on that Payment method and choose Orders where Payment Method is Credit Card by Traffic source.