Online marketing campaigns - email, paid search, affiliate marketing, banner ads and shopping comparison-site placements - have played a larger role than usual in shaping shopper behavior early in the holiday season, according to Coremetric's LIVEmark Index benchmark data. The number of visits to retail sites driven by online marketing increased by one-third from the week prior to Thanksgiving to the week after; moreover, as a result of heavy discounting, there was an increase in conversion rates but a decline in average order size for retailers.

Visits driven by marketing increased 13 percent from the week starting November 14 to the week of the Thanksgiving holiday, starting on November 21, according to Coremetrics data.

In the week after Thanksgiving, starting on November 28, marketing-driven visits increased 33 percent over the week prior to the holiday. The gains in marketing-driven traffic outpaced the overall holiday-shopping-induced increases in site traffic of 9 percent and 24 percent, respectively, for the two weeks.

Retailers' discounting may have accelerated purchases, but it came at a cost. In the week following Thanksgiving, conversion rates for visits to leading retail sites increased some 24 percent from the week prior to Thanksgiving, but average order size fell 3.5 percent.

However, the increases in traffic and conversions resulted in a revenue increase of 47 percent for the week following Thanksgiving, compared with the week prior.