Big advertisers to buy ads by the quarter, not the yearBad news for TV, print and radio: heavy-spending packaged goods advertisers, such as $300 million-a-month Procter & Gamble, don't want to make annual ad-planning commitments anymore. Due to rising fuel, food, and commodity costs, these advertisers only want to commit to spending quarter by quarter. "The planning cycle has changed," Martha Stewart Living Omnimedia president Wenda Harris Millard told Silicon Alley insider. "This is wreaking havoc on media company forecasting." What Millard meant, of course, is old-media forecasting. Other than maybe Yahoo, AOL and MSN, Web companies aren't used to the luxury of sending customer invoices a year ahead of time.