• by Gavin O'Malley  @mp_gavin, February 4, 2011

In the fourth quarter of the year, online retail spending reached a record $43.4 billion -- up 11% year-over-year, according to comScore. The rate represented the fifth consecutive quarter of positive year-over-year growth and the second quarter of double-digit growth in the past year.

Still, as comScore chairman Gian Fulgoni notes, the positive trend is not for lack of trying on the part of brands and retailers.

"Retail e-commerce had a strong fourth quarter ... as holiday season spending was bolstered by an improving sentiment among some consumer segments and by retailers' discounting and promotions," Fulgoni said.

The top-performing online product categories were computer software -- excluding PC games; consumer electronics; books and magazines -- excluding digital downloads; computers/peripherals/PDAs; and toys and hobbies. Year-over-year, each of these categories grew at least 15% in the fourth quarter.

The top 25 online retailers accounted for 68.4% of dollars spent online -- up 5.6 percentage points compared to a year ago.

However, this percentage represented a decline from the third quarter of 2010, during which the top 25 retailers accounted for 69.9% of dollars -- an indication that small- and mid-sized retailers are also rebounding from the recession, according to comScore.

Meanwhile, 84% of U.S. Internet users conducted an online transaction in the fourth quarter of 2010 -- up from 78% year-over-year. The average buyer spent about the same amount online during the most recent quarter as they did last year.

"The 2010 holiday season saw the first billion-dollar day on record and several more surpassing $900 million to help propel Q4 to record spending levels," Fulgoni added. "We anticipate that the progress we've seen in the past year as we climbed out of the recession will continue with sustained double-digit growth rates in 2011."