Agonizingly slow Web sites. Maddening error messages. And, most frustrating of all, unavailable home pages.
Online shoppers intent on skipping long lines and clogged parking lots at the mall are discovering a different kind of traffic problem this holiday season: overcrowded Web sites that are cracking under the pressure.
Since Thanksgiving, some of the biggest names in online retailing -- Amazon.com, Kmart.com and Sears.com among them -- have experienced significant glitches that blocked visitors from making purchases, according to industry analysts and research firms.
"The story of this holiday season, for the big retailers online, is a surprising amount of inconsistency," said Matthew Poepsel, director of product management at Gomez Inc., a firm that tracks Web site performance.
Analysts blame the holiday hiccups on a dramatic jump in online traffic, propelled by a crush of new Web-only sales promotions and the rapid growth of high-speed Internet access at home, which has extended peak Web browsing times from the traditional working hours well into the night.
Holiday sales have already reached $11.1 billion, a 23 percent increase over the comparable period of 2003, according to ComScore Networks Inc., a research firm that tracks online sales. On several retail sites, such as Walmart.com, HomeDepot.com and Staples.com, traffic is up 50 percent or more, the firm found.
But the troubles are a potent reminder that the 10-year-old business of Web retailing, known as e-tailing, is still very much a work in progress. Every year, retailers spend millions of dollars to upgrade their Web sites, but analysts say there is still no foolproof method for protecting against overloads.
"It is still a very young discipline," said Matthew Rechs, chief technology officer at Schematic, a Los Angeles technology company that has designed Web sites for retailers. "The reality is that we don't know that much about how to predict Web traffic."
Overloaded by consumers lured by its $500 sweepstakes, Kmart.com experienced a major slowdown on its Web site the weekend after Thanksgiving, making it inaccessible for extended periods, analysts said.
The retailer had aggressively advertised the promotion online and in its stores "so the response was overwhelming," said Kmart spokeswoman Caryn Klebba.
