• by Gavin O'Malley  @mp_gavin, November 27, 2011

Online retailers had high hopes for this holiday shopping season, and, according to preliminary data, they’re getting their wish. Indeed, online sales on Thanksgiving Day were up 39% over last year, according to IBM’s Coremetrics retail data.

By midday on Thanksgiving, online sales were already 20% over results from the same period a year ago, Coremetrics found.

Showing mobile’s gaining prominence, the number of consumers using their handsets to window shop hit a record 15.2% -- up from 6.45% during the same period last year. The number of consumers using their mobile device to actually make a purchase rose 11.09% -- up from 4.25% in 2010.

During the first 20 days of the holiday season -- which began on Nov. 1 -- consumers spent $9.7 billion online, according to new comScore. That represented a year-over-year growth rate of 14%.

For the entire 2011 holiday season -- from Nov. 1 through Dec.31 -- domestic online retail spending will reach $37.6 billion, representing a 15% year-over-year gain, comScore estimates.

Such a gain would represent a nice improvement over last season’s 12% year-over-year increase.

What’s driving sales? For one, consumers indicated that they believe retailers’ promotional activity for the early part of the season had increased in relation to last year.

Specifically, 33% of respondents indicated that they are seeing more discounts, sales and promotions versus last year, compared to just 7% who said there were less.

As with past years, one of the more prominent incentives for online purchases remains free shipping. When asked how important free shipping is for making an online purchase this holiday season, slightly more than three-quarters -- 76% -- of consumers indicated it was important, while 47% indicated they would abandon a purchase if they got to checkout and found that free shipping was not included.