Sears, Saks Fifth Avenue, Costco, Dell, Victoria's Secret, Bloomingdale's and Williams-Sonoma all saw their sites malfunction at some point between Friday and Monday, according to companies that monitor Web performance.
The day after the Thanksgiving holiday in the U.S., known as Black Friday, is a big shopping day and kicks off a major weekend for retailers that ties in with giant online sales on what is known as Cyber Monday.
Online stores that slow to a crawl, return error messages or collapse altogether are the bane of retailers, since those problems are a major turnoff for prospective buyers and, depending on their severity, can seriously hurt sales.
Most of the problems affected checkout processes, very possibly leading to lost sales at a point when customers were about to make a purchase, said Shawn White, director of external operations at Web monitoring company Keynote Systems. "Checkout is obviously the most critical part of the online shopping experience," White said.
This problem reflects a common oversight on the part of online retailers: load testing their entire e-store, not just the home page, he said.
Keynote, which monitors the performance of 35 major online retailers, flagged Sears' Web site as one experiencing major difficulties on Friday. Sears.com was mostly unavailable between 10 a.m. and 12:30 p.m. Eastern Time, and again between 1:30 p.m. and 5 p.m., White said.
Another retailer in trouble was Saks Fifth Avenue. Between 7:30 a.m. and 1 p.m. Friday the Saks home page became up to 10 times slower than normal and didn't load at all for half of its visitors, he said. Gomez, another Web monitoring company, said the availability of the Sears Web site dropped to around 61 percent Friday before recovering on Saturday.
Both Sears and Saks displayed a Web page notifying visitors of the technical problems when their sites weren't loading properly, White said.
"Sears.com is now fully functional and we continue to monitor the volumes [of traffic] and take steps to ensure the site can continue to serve our customers," a spokeswoman for Sears said via e-mail. "Friday, due to higher than anticipated peak volumes, traffic was interrupted, but Sears.com is operating fine today as it did all weekend. Please note that the site was never down per se; it experienced intermittent interruptions.
On Monday starting at around 11:30 a.m. and lasting at least until 5 p.m., J. Crew's Web site was completely down, according to White.
Bloomingdales.com was also down for most of Monday, greeting visitors with the message: "Thank you for visiting bloomingdales.com. We are in the process of upgrading our site to better serve you. We cannot offer our online experience at this time. We apologize for the inconvenience."
Starting at 10 a.m. and lasting until at least 2:30 p.m. on Monday, the Victoria's Secret shopping cart was returning error messages when customers tried to place items in it, according to Gomez.
Also having problems at the shopping cart level was Williams-Sonoma's Web site, which experienced slowdowns of almost 50 seconds between 7 a.m. and 9 a.m., before returning to a more normal response time of 24 seconds at 10 a.m., Gomez said.
At Dell's Web site, returning shoppers were unable to retrieve previously entered account information between 9:40 a.m. and 10:15 a.m., forcing them to re-type the data at checkout time, Gomez said.
However, a Dell spokesman said the company hadn't noticed the issues described by Gomez. "We're not aware of the problems described in this report. We haven't gotten any complaints from our customers regarding the performance of our Web site," said spokesman Bob Kaufman.
Both Gomez and Keynote report that Costco had availability problems at times on Friday, while Gomez also noted that Hewlett-Packard's HP Shopping store and Overstock slowed down on Friday.
Overall, the 35 sites tracked by Keynote did better on aggregate this weekend than during the comparable weekend last year. This year, 15 percent of the sites encountered minor to significant performance issues, down from 30 percent last year, White said.
The best tip to avoid Web site performance difficulties: Prepare early.
"The biggest lesson for retailers having problems with their Web sites is that they need to start preparing for Black Friday in January," Keynote's White said.
Costco, Williams-Sonoma, HP, Saks, Victoria's Secret, Bloomingdale's and J Crew didn't immediately respond to requests for comment.