One technique to boost the income from your sales commission program is to have an exit pop-up, asking people to take some action as they're leaving your site. You might ask them to sign up for your newsletter , register for your members' only area or make them a special limited time offer on one of your products.
While many people do have popup blockers installed these days, not everyone does. And, for those that do not have a blocker installed, you'll get one more chance to entice them to take action.
*Many people hate pop up ads, but marketers use them because they work.