• by Mark Walsh  @markfwal, September 19, 2012

When it comes to mobile shopping, Amazon is by far the top retail destination, according to new findings from comScore. The e-commerce giant drew 49.6 million unique visitors to one of its mobile sites or apps in July, or 46.6% of U.S. smartphone owners, according to new comScore data. 

eBay was a distant second with a smartphone audience of 32.5 million, or 30.6%, followed by Apple, 17.7 million (16.6%), Wal-Mart, 16.3 million (15.3%), and Target, 10 million (9.4%). Other brands in the top 15 with single-digit shares included Best Buy, The Home Depot, Blockbuster, Barnes & Noble and Etsy.

Overall, four out of five smartphone owners -- 85.9 million people -- accessed retail content on their device in July. “The retailers that best understand how consumers are engaging in mobile shopping behaviors and design their strategies accordingly will be best positioned to capitalize on these shifting market dynamics,” stated Mark Donovan, comScore SVP of mobile.

Beyond retailers, the study pointed out mobile shopping app shopkick saw its audience reach 4 million in July, highlighting another way that consumers are turning to mobile as part of their shopping experience. Shopkick works with retail partners including Target, Macy’s, Best Buy and American Eagle Outfitters, offering in-store incentives via its app.

Given that the iPhone and Android handsets dominate the smartphone landscape, comScore also looked at differences between the two in relation to mobile shopping. Amazon was still tops across both operating systems, but Apple garnered a much bigger audience among iPhone users, with 33.5% visiting the company’s retail presence compared to just 7.3% of Android users.

Looking at demographics, comScore found that female visitors accounted for a higher proportion of time spent on retail destinations on both the desktop and in mobile. On the PC, women represented 53.4% of time spent on retail sites, and 56.1% of the time shopping on smartphones. The retail audience was split about evenly between men and women on both platforms.

Smartphone shoppers also skewed younger than those shopping on desktop or laptop computers, with 71% under the age of 45 compared to 61% of PC users. Younger users also drove higher engagement levels on phones. Those under 45 accounted for nearly three of every four minutes spent on retail content via smartphones versus 62% of retail minutes on desktop computers.

Smartphone retail audiences were also more likely to be affluent than PC users, as a result of smartphone ownership skewing to higher-income households. Almost one in three smartphone shoppers had a household income of $100,000 or higher, with this segment accounting for a comparable 31% of minutes spent on retail sites and apps.

The comScore study did not include any findings on actual mobile transactions. But a recent IBM benchmark report showed mobile commerce accounted for 15% of all online sales in the second quarter, up from 8% a year earlier.