Forrester expects this holiday season to generate $68.4 billion in US online sales, a 15% increase over 2011’s total and 3% higher than the expected overall annual online retail growth rate. “This year’s optimism is in large part due to an ever-increasing number of consumers choosing the Web over physical stores and the rise in mobile commerce,” notes Forrester Vice President and Principal Analyst Sucharita Mulpuru in new report released today. “The average US shopper will spend $419 dollars online this holiday season — a 12% boost from last year — as they continue to go to the Web to take advantage of the increasing number of digital offerings from retailers.”

That said, while tried-and-true holiday promotions will continue to be effective, retail execs need to ensure that they are set up to support (and retain) the cross-channel, deal-hunting shopper to maximize online and online-influenced sales. For instance, retailers should expect aggressive holiday show-rooming and be prepared for mobile shoppers, ensuring critical content is available (and tested) on mobile devices.

For more information on the US online holiday retail forecast, visit the Forrester blog here.