The magic word driving online sales this year is “Free Shipping” however, last-minute discounts help too. More than $22 billion has been spent online during the season-to-date, marking an 18% gain versus the corresponding days last year. Monday, December 10th reached $881 million in sales (up 33%), registering as the heaviest online spending day of the season and the heaviest online spending day on record. comScore says its data show that this years 18% online retail spending growth rate stands well below the 26% rate at the same time last year. An analysis of online spending by household income reveals that slower growth among lower income households is weighing on the overall season-to-date growth. While households earning at least $100,000 have increased their online spending 28% versus year ago, households making less than $50,000 have increased their spending by just 10%. comScore anticipates that spending at the beginning of this week will again be strong with most free shipping deals available until Tuesday, December 18th.