Wal-Mart.com's Elmo doll promotion earlier this week drew thousands of holiday shoppers anxious to buy the hard-to-find toy, and caused 45 minutes of performance problems, including a brief outage, a Web metrics firm said Friday.

Wal-Mart Stores had confirmed that it had problems Wednesday as a result of the promotion, but offered few details. But Keynote Systems said the retailer's online shopping site started having problems at noon Eastern time, and didn't get back to normal until about 12:45.

"According to our measurements, the Wal-Mart site was significantly degraded during this brief period and, in fact, took the entire site down for a short period of time," Keynote spokesman Josh Danson said in an e-mail.

Wal-Mart had offered limited quantities of the doll to drive more traffic. The retailer, however, got more than it bargained for, saying the site experienced an "incredibly high traffic volume." After apparently beefing up its servers, Wal-Mart started offering the doll again at various times on Thursday and Friday.

Elmo is a character in the kids' TV show Sesame Street on PBS. When activated, the battery-operated toy has the character falling and squirming in fits of laughter.

Wal-Mart, which also reportedly had site problems the Friday after Thanksgiving, is not the only major retailer to have some hiccups during the holiday shopping season. Consumer electronics chain Best Buy, experienced Web site downtime from late Thursday night until 8:30 a.m. Eastern time the following morning, according to Internet retailer monitoring service, WebSitePulse.com.