NEW YORK — After jamming malls on Friday for discounted flat-screen TVs and toys, shoppers clicked onto their computers at work yesterday as retailers ushered in the start of the online shopping season with bargains and marketing hype.

With an increasing number of online players trying to outdo one another, shoppers are being bombarded with even more generous discounts, free shipping offers and other enticements this holiday season.

For the Monday after Thanksgiving, coined Cyber Monday by the National Retail Federation, plenty of retailers such as Circuit City Stores Inc. offered special one-day coupons. Meanwhile, Walmart.com yesterday began a five-day special on such online-only items as certain flat-screen TVs and cashmere scarves. And Barnesandnoble.com is wooing shoppers with a free tote bag if they spend $75 or more.

Jewelry retailer ice.com reported a 60 percent increase in traffic and an 80 percent increase in sales through noon yesterday, compared to the same period a year ago, said Pinny Gniwisch, founder of ice.com. Walmart.com reported a 60 percent increase in traffic through noon yesterday compared with a year ago.

Still, Cyber Monday marks the first big online shopping surge for many merchants for the season.

ComScore, which excludes travel, auctions and corporate purchases in its results, expects online sales to increase by at least 24 percent to $599 million, from $484 million a year ago. ComScore reported a better-than-expected 42 percent increase in sales to $434 million on the day after Thanksgiving, from the same day a year ago.

The online shopping surge yesterday follows a strong start to the holiday shopping season for brick and mortar stores over the Thanksgiving weekend.

One exception was Wal-Mart Stores Inc., which announced Saturday that November's same-store sales would be more disappointing than expected. The glum outlook sent its stocks down yesterday, as investors worried about the strength of the retail sector.

Nevertheless, analysts are expecting a robust holiday season for stores and in cyberspace, though business will be slower than a year ago. The National Retail Federation expects total sales for the November and December period to be up 5 percent, but not as high as the robust 6.1 percent pace seen a year ago.

As for online holiday sales growth, Jupiter Research forecasts an 18 percent increase for online sales to $32 billion. That is slightly below the 23 percent pace in the previous year.

Analysts are carefully monitoring the rivalry between online-only stores and brick and mortar stores, which are overtaking the lead in the online market share wars. According to comScore, from 2003 to 2005, sales growth for brick and mortar stores' online divisions grew twice the rate of that of online-only merchants.

Stores that operate both e-commerce sites and physical stores are realizing they can "use the Internet to not only sell product but also drive traffic to their stores," said Gian Fulgoni, chairman of comSCore Networks.

Consumer electronics retailer Circuit City offered special coupons just for yesterday, including additional savings of $100 on TV purchases of $1,700 and up, as well as an additional $50 savings on home audio systems purchases of $400 and up.

Throughout the holiday season, Circuit City is giving $24 gift cards to customers if their online order is not ready for pick up at the stores in 24 minutes.

Walmart.com, which redesigned its Web site this month, yesterday unveiled 50 online-only specials offers, from cashmere scarves to flat-panel plasma TVs, that will be available through Dec. 1. Carter Cast, CEO of walmart.com, said it will be replacing sold-out items with new offers this week.

The pure-online players are fighting back with free shipping and other deals.

Amazon.com pushed shoppers to get started early by holding a poll to select one steeply discounted gift item to be offered in limited supplies beginning on Thanksgiving.