Suddenly, the advertising trade press is abuzz with a new concept: "shopper marketing." According to a draft study by Deloitte from the Grocery Manufacturers Association, the investment in in-store advertising has doubled since 2004 and is on pace for compound annual growth of 21% through 2010. The only surprise in this is that anyone finds the findings surprising. Conventional wisdom, backed by solid if not conclusive research, says that more than 70% of purchase decisions are made in-store. Yet despite that, in-store advertising still represents only 6% of marketing budget allocations, according to Deloitte.