This was especially troubling as it happened on the so-called Black Friday, where major retailers hope to see their financial ledgers go from being in the red to being in the black.

This trend, however, may be changing, as online sales start to challenge brick-and-mortars for market share and as the day after Thanksgiving starts to become a much less significant day for e-commerce players. The most important date for e-commerce players may instead be late in December. One industry report placed the new date as Dec. 18.

Keynote Systems, which tracks Web traffic, said the Wal-Mart site, www.walmart.com, was "effectively down" from 4:30 a.m. EST Friday until 2:30 p.m.

Friday morning, according to Ben Rushlo, a Keynote senior manager of competitive research, the site of the nation's largest retailer was eight times slower than normal, with many customers unable to even reach the home page. "Every request was either completely down—with an error message—or unusually slow," he said.

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Things changed at 1:15 p.m., when the site went down completely, apparently a deliberate move by Wal-Mart to try to fix the problem. Users were then greeted with a Wal-Mart maintenance page. About an hour later—at 2:30 p.m.—the site was up and functioning without problems.

A Wal-Mart spokesperson—Amy Colella—was quoted by the Associated Press as blaming the problems on a "higher than anticipated traffic surge." But 4:30 a.m. seems to an unusually early time for such a surge, especially given that Wal-Mart's site would presumably have been prepared for a huge traffic surge on Friday anyway.

That said, this year did see extremely early traffic surges at Wal-Mart's brick-and-mortars, which absolutely would have prompted an online traffic spike. Ironically, the E-Commerce player that had been having periodic outages this year—Amazon—had a very uneventful day on Black Friday. One possible reason is that, unlike brick and mortars like Wal-Mart and Macys, Amazon is obviously always open 24x7, so it is less exposed to huge traffic surges as would Wal-Mart when it opens early for special events. Reports of huge lines out of Wal-Marts at 4 AM were flooding the Web.

Some industry observers speculated that it might have been an outsourced data center that was cause of the problem. Completely overloaded routers could have triggered such a situation, but the time of the impact makes that less likely. Another scenario was a denial-of-service attack, but the pattern of when the servers were back up makes that a less likely scenario

Another key retailer who had problems on Friday was Macy's. The parade people suffered what could be called The Disaster on 34th Street starting at about 4 a.m., when its site, www.macys.com, was returning almost 100 percent error rates, according to a source familiar with Macys.com's Web operations but who requested anonymity. Its performance dropped to one-sixth normal response time, and it didn't get repaired until about 2:15 p.m.

The closeness in the times of both Macy's and Wal-Mart's outages—starting at 4 a.m. and 4:30 a.m. and being resolved at 2:15 p.m. and 2:30 p.m., respectively—raised initial questions about whether it was an Internet-wide problem, but the strengths of many other retail sites make that explanation less likely. The possibility that both sites were using the same data center seems more likely, although that could not be confirmed.

On the good news front, the e-commerce giant that was most closely watched on Friday—Amazon.com—fared quite well, after some well-publicized outages. Amazon had a small hiccup on its site on Thanksgiving, but fared well on Black Friday, Rushlo said. "Amazon.com has been virtually perfect over the last two days, with no performance slowdowns and only a small period of performance stress when the Xbox 360 promotion was occurring," he said. "Amazon.com was clearly ready for the holiday rush."

Retail Center Editor Evan Schuman can be reached at Evan_Schuman@ziffdavis.com.

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