Black Friday intensity grows Like shoppers jostling to grab the best Black Friday bargains, retailers are gearing up to fight over a limited pool of consumer dollars as the holiday shopping season kicks off this week, bringing to the battle new tactics such as ever-earlier opening hours, in-store entertainment and mobile promotions. Online taxThis year for the first time, Californians will have to pay sales tax for Black Friday purchases they make online, but it's not clear if that will send many would-be online shoppers into stores, said Kirthi Kalyanam, who is director of the Retail Management Institute at Santa Clara University. Surveys show that shoppers prize deals above all else, and online retailers are often able to beat brick-and-mortar stores on price. "Service, manufacturing, public transportation ... (and) football players have to go to work on Thanksgiving," she said. Besides staying open for longer hours, retailers are tweaking their events to encourage customers to stay in the store longer and to spread the crowds out across the hours. All this is in addition to tactics stores are already using to fight showrooming, the popular practice of using stores merely as a place to check out a product that you intend to buy online. Both showrooming and aggressive price comparison have become major forces for retailers to contend with now that so many shoppers are equipped with smartphones, with apps that scan bar codes and pull up prices from competitors both online and in the neighborhood. Target will now match prices from certain online competitors' websites during the holiday season, in addition to matching prices in competitors' print ads. Walmart is offering the chance to buy some doorbusters online on Thanksgiving before the store opens - exclusively to customers who download the store's mobile app, join the e-mail list or "like" the company on Facebook, said Walmart.com spokesman Ravi Jariwala.