Mobile commerce became an increasingly important factor in web retailing during the 2011 holiday season as more retailers saw significant increases in mobile traffic and mobile sales.

IBM, for example, reports 18.3% of all traffic to online retail sites came from a mobile device on Christmas Day, up from 8.4% a year ago. Overall, consumers using mobile devices accounted for 14.4% of the day’s sales, up from 5.3% on Christmas Day a year ago.

The holiday season was quite mobile at Gilt Groupe: 20% of all sales during November and December stemmed from mobile devices.