If traffic were sales, e-commerce merchants had plenty of reasons to smile this holiday season as one measurement firm reported today that the number of visitors to shopping sites was up 50 percent from 2000 and 95 percent from 1999.

New York City-based Jupiter Media Metrix said that on average, 51.3 million unique visitors went to e-commerce sites each week during the 2001 holiday-shopping season (defined as the week ending Nov. 25 through the week ending Dec. 23).

"...we're left with one inescapable truth -- the Internet has become an integral part of holiday shopping," said Charles Buchwalter, vice president of media research at Jupiter Media Metrix.

"Unlike 2000, when online shopping started strong but then fell off, online shopping this year started strong and ended even stronger," he said.

Meanwhile, the eSpending report, released today by Goldman Sachs, Harris Interactive and Nielsen//NetRatings, shows that $13.8 billion was spent online during the 2001 holiday season (not counting travel) for a 15 percent year-over-year increase. At the peak of the season, the first week of December, one in five Internet users, made a purchase online, that study said.

And according to BizRate.com, the comparison shopping site and a provider of e-commerce research, fourth quarter online sales increased by 35 percent to $12.4 billion.

Regardless of whose e-commerce statistics you take to heart, analysts at Goldman Sachs are cautioning that online holiday sales were in line with forecasts - up about 30 percent year over year - and they are warning investors not to believe hype from privately held companies boasting about dramatic sales gains of 70 to 80 percent.

In an advisory to clients, GS said that its estimate of online sales over the 11 weeks ending Dec. 28 showed an increase of about 30 percent year over year to $16.3 billion, "in line with our full year 2001 estimated increase of 20 percent to 25 percent."

That said, GS still expect sales growth deceleration from lack of channel shift, "but importantly satisfaction was up significantly versus a year ago," something that the investment research firm sees as "positive for continued adoption and potentially 'crossing the chasm' to reach mass market by '03."

As for the online merchants, 2001 may have been the year of the traditional retailer, according to Jupiter Media Metrix.

"We've been waiting for the inevitable dominance of the traditional retailers over their pureplay counterparts, and it appears that 2001 may have been the year when it finally happened," said Ken Cassar, senior Jupiter Research analyst.

"With a few exceptions such as Amazon, the dominant retailers that sell merchandise directly from their sites tend to be affiliated with brick-and-mortar stores and catalogs. In fact, traffic to the seven traditional retailers among the top 15 shopping sites for the entire 2001 shopping season increased 73 percent versus last year."

The top three traditional retailers according to their average daily unique visitors each week over the 2001 holiday-shopping season were: Columbia House Sites with 598,000 average daily unique visitors; Toysrus with 515,000; and Barnesandnoble.com with 447,000.

eBay leads the pack overall however, with a 2001 shopping season average daily visitor count of 4.51 million, followed by Amazon.com with 2.5 million. Rounding out the top five were MyPoints.com with 2 million daily visitors, BizRate.com with 683,000 and eBay's Half.com with 660,000.