The most recent week ending Dec. 6 reached $4.6 billion in holiday spending, heavier than any individual spending week in 2008 but still below two individual weeks in 2007. The week began with strong weekday spending, led by $887 million on Cyber Monday, but ended on a softer note with negative year-over-year growth rates during the weekend.

"After a strong beginning to the week, we saw growth rates decelerate over the weekend to put this past week of holiday shopping in line with our 3 percent growth forecast for the season," says comScore chairman Gian Fulgoni. "We are anticipating heavy spending for the current week, making it an important determinant for how the holiday season as a whole will perform. Hopefully, we'll see a return to the growth rates we observed during the earlier part of this past week and that the weekend softness was just a temporary hiccup."