Stock and computer system woes yesterday simultaneously hit eBay.com, the No. 1 online auctioneer, preventing Web surfers from using the site and prompting its shares to drop as much as 11 percent.

Yesterday's crash came at an inopportune time for site owner eBay Inc., which is readying itself for an open house for Wall Street analysts on Monday morning. But eBay officials said they don't expect the outage to affect the open house.

"One of the challenges of being a pioneer in this field is that we have growing pains," said Steve Westly, eBay's vice president of marketing and public development.

EBay shares recovered slightly later in the trading day to close at $83.25, down $9.62 1/2, or 10 percent, on the Nasdaq Stock Market.

EBay first went down in the early morning hours for weekly maintenance. Then, company officials said, problems caused the outage around 7:30 a.m. Those were quickly corrected, but "network anomalies" occurred when the system was rebooted.

The site remained down until the late evening. EBay auctions scheduled to end yesterday during the outage time will be extended for 24 hours.

This crash is the latest in failures that have included four outages in July and a 21-hour outage June 10. The company said the June 10 outage could cut as much as $5 million from its second-quarter revenue.

After the last outage, eBay officials promised vendors to do everything they could to prevent further system failures. But Eric Slone, an eBay vendor, said yesterday's crash was evidence that they didn't fulfill their promises.

EBay's problems could create inroads for competitors. Currently, eBay receives on the average roughly 1.2 million different visitors a day, according to Internet traffic measurer Media Metrix Inc. While eBay isn't the only auction site to have outages, its shutdowns may prompt customers to test rival auctions sites run by Yahoo Inc. and Amazon.com Inc., some analysts said.

Because "eBay is highly visible, when they have a problem, everyone knows about it, it gives you some cause to be concerned," said David Zale, an Internet analyst with investment advisers Sands Brothers & Co.

Associated Press and Bloomberg reports were used in compiling this report.

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