Consumer spending accounts for a mammoth two-thirds of total US economic activity, and the annual summit of that spending occurs over the end-of-year holiday season. This year economists are forecasting a retail record, but the dynamics of the splurge are undergoing fundamental changes. Among other trends, approximately 45% of Holiday shoppers intend to begin making purchases before November, and 57% of those purchases will be made online. Here are three fundamental ways that the all-important holiday shopping season is changing. Presented by @cmegroup: