E-commerce companies may truly have a Merry Christmas this year.

U.S.consumers have spent $9.67 billion online in the first 20 days of the holiday season, according to digital research firm comScore. This is up 14 percent from $8.47 billion last year.

By the end of the holiday season, comScore expects a 15 percent gain versus a year ago in e-commerce sales, totaling $37.6 billion. The analytics firm measures the holiday season as the month of November and December.

With the persistent backdrop of macroeconomic uncertainty and continued high unemployment, consumers appear to be increasingly favoring the online benefits of convenience and lower prices, Chairman Gian Fulgoni said in a statement.

The totals include sales from sites dedicated to online retail, such as Amazon and eBay, and sales from company's online shopping unit. The figures exclude travel purchases, auctions and large corporate purchases.

As many brick-and-mortar stores have pushed up the dates when deals become available, e-commerce retailers have also pushed up the dates when deals begin.  

One thing online consumers are demanding is free shipping. In a survey sent out by comScore to about 1,000 customers, more than three-quarters (76 percent) said they believe free shipping is important. In fact, 47 percent of customers said they would abandon a purchase if they went to checkout and found that free shipping wasn't included.