Holiday Web sales are running ahead of forecast as online gift certificates helped give Internet retailers a chance to participate in U.S. consumers' last-minute shopping spree, Internet research firm comScore Networks (search) said on Wednesday.

Online sales from Nov. 1 through Dec. 26 were $14.8 billion, up 29 percent from a year ago, comScore said. The figure excludes travel and auctions.

If that growth remains constant, online sales from the November through December holiday season would be $15.8 billion. ComScore had originally forecast sales rising as much as 26 percent to $15.5 billion.

Internet sales have been a bright spot for the overall sector, which this year is expected to ring up holiday sales of $219.9 billion, a year-on-year increase of 4.5 percent, according to the National Retail Federation.

From Dec. 20 to Dec. 26, Web sales jumped 53 percent from a year ago to $1.22 billion.

The flowers, gifts and greetings category — which includes gift certificates that can be immediately delivered via e-mail — was the Web's top gainer.

"For the first time, online retailers were able to participate in late-season buying," comScore spokesman Graham Mudd said.

During the year, Web retailers have made operational improvements that allowed them to ship later into the season. They also have benefited from strong ties with shippers such as United Parcel Service Inc. (UPS)

Computer giant Dell Inc. (DELL) had a promotion that promised to deliver orders in two days, comScore said.

This year, consumers were more willing to pay for fast shipping on sometimes hard-to-find items, such as Apple Computer's (AAPL) iPod digital music player, comScore said.

On other fronts, some brick-and-mortar retailers sidestepped the shipping issue by allowing Web buyers to pick up items at local stores, or by offering to deliver those items from local stores.