"Half my advertising budget is wasted, but I don't know which half," goes the old retailer's quip, but this dilemma may someday be a thing of the past. If so, affiliate marketing, a type of pay-for-performance advertising, will get some of the credit.

It is an approach to marketing that is rapidly catching on with companies looking for a new, cost-effective way to reach customers.

Leading the charge are companies like Tokyo-based ValueCommerce Co., whose president, Brian Nelson, explains the idea behind affiliate marketing: "(Clients) don't have to waste money on advertising. You're only paying for the benefit."