Online shoppers took the Web by storm Monday, though shares in the big Internet retailers mostly failed to celebrate. The first Monday after the Thanksgiving holiday is becoming the start of holiday shopping for Web merchants, just as Black Friday has long heralded the start of the high season for bricks-and-mortar retailers. A Shop.Org/BizRate survey found that 77% of online retailers were seeing a "substantial" increase in sales on what is now being called Cyber Monday. "On Cyber Monday, consumers set their sights on surfing for holiday gifts and shopping online," said Scott Silverman, executive director of Shop.Org, a trade association, in a statement. "This year, online retailers will be capitalizing on the increased traffic by offering special promotions and discounts." By 11:35 a.m., online merchants were seeing more than 1.6 million visitors per minute from North America, against 550,000 before 8 a.m., according to Akamai, which hosts Web sites for more than 1,800 companies. At midday on a typical Monday, these sites get 1.3 million visitors per minute. Amazon.com ( AMZN), the largest Internet retailer, has said it's expecting its "busiest-ever" holiday season. Since Nov. 1, more than 44 million items have been ordered from Amazon's Web sites, according to the company. Cyber Monday mania also helped boost the Seattle-based company's share price by 48 cents to $48.54. Listings on eBay ( EBAY), the top online auction site, are tracking ahead of the estimates of Merrill Lynch analyst Justin Post, according to a note. But shares of eBay, based in San Jose, Calif., were down 57 cents to $46.14. Non-travel online spending rose 24% from a year ago to $6.96 billion for the first 25 days of November, according to data from comScore Networks. Consumers continue to use their high-speed connections at work to make purchases there despite the proliferation of fast Net service at home, ComScore says.