A customer is visiting your e-commerce Web site. She’s decided to do more online shopping this holiday season to save on gasoline and find the lowest prices. She’s using a Mac running Safari, but your site is optimized for Internet Explorer 7 and your development budget is mainly focused on preparing for IE 8. She selects a few products and heads for the shopping cart, but the “checkout” button isn’t available. Frustrated, she’s off to another site. You’ve lost the sale.