The day after Christmas, traffic to the retail websites in the Nielsen/NetRatings eShopping Holiday Index grew 35 percent year over year, from 20.9 million in 2005 to 28.1 million in 2006.

Online shopping has become a part of the holidays, with 29 percent more unique visitors to Index sites this Christmas day than last year's, according to Nielsen/NetRatings. The biggest online shopping day of the holiday season was Dec. 12, with 30.4 million unique visitors to the eShopping Holiday Index (see Table).

eBay led the top shopping destinations with a unique audience of 12.4 million on on Dec. 12, followed by Amazon with 6.1 million and Wal-mart.com with 4.0 million.

The week ended Dec. 3 was the peak week this holiday season, with visits to the Index increasing 43 percent over the base week (the last week in October). Lego, Macy's and Office Depot led the year-over-year fastest growing online shopping destinations that week, with traffic increasing 120, 70 and 64 percent, respectively.

Visits to shopping comparison websites also peaked during the week after Thanksgiving, increasing 75 percent from the start of the season to a total of 64.0 million shopping trips.

During the week ended Dec. 24, there was a 24 percent week-over-week decline in the use of these online comparison tools, from 60.1 million visits to 46.1 million. But the week ended Dec. 31 registered another uptick, growing six percent to 48.7 million shopping trips.