• by Mark Walsh  @markfwal, May 1, 2012

During the holiday season, IBM issued a series of benchmark reports showing steep year-over-year gains in the proportion of online retail traffic and sales coming from mobile devices. That pattern held steady through the first quarter, with the share of mobile sales increasing to 13% from 7% a year ago, and mobile traffic growing to 17% from 6%.

That compares to a doubling of the mobile sales share to 11%, and a near tripling of mobile traffic to 14.6% from 5.5%, during the peak shopping period in December.

“The good news is we didn’t dip back down after the holidays, so it wasn’t a one-time anomaly or some sort of seasonal trend. The mobile numbers held strong through Q1,” said Jay Henderson, strategy program director, cross channel marketing for IBM. The data comes from the company’s first-quarterly report tracking online and mobile retail trends beyond the holiday season.

IBM intends for its quarterly research on Web-based retailing to serve as the online companion to the advance monthly retail and food services report issued by the U.S. Census Bureau. Online retail sales in the quarter overall dipped 1.9% from a year ago, but showed signs of a rebound in March, increasing 6.3% from the prior month.

Mobile growth has remained a bright spot. “One of the things we’re starting to see is the arrival of the post-PC consumer as these mobile platforms get such strong adoption,” said Henderson. “A whole new paradigm is emerging around the commerce experience being driven by the mobile phone trend as well as by tablets,” said Henderson.

The iPhone was the top device in the first quarter, accounting for 6.5% of visits to retail sites, followed by Android devices as a whole, at 5.9%, and 5.3% using the iPad. IBM’s December report also showed the Apple tablet was the leading device when it came to m-commerce, with conversion rates reaching 6.3% versus 3.1% for all other mobile devices. The conversion rate data wasn’t updated in the first quarter.

IBM doesn’t break out information on retail categories within mobile. But top-performing areas for online overall in the quarter included home goods, up 29.3% from a year ago, health and beauty (28.8%), department stores (20.4%), and apparel (14.9%).