• by Chuck Martin , Staff Writer, August 27, 2013

While mobile commerce may not be front and center for all merchants, that doesn’t mean it isn’t happening in a big way and across the board.

Mobile shoppers are increasingly tapping into retailers’ websites from their mobile devices and it turns out there’s a correlation between what’s viewed and the viewing device.

In a new look at mobile commerce, comScore is delving more deeply into behaviors in an attempt to identify the differences in sales by product category based on device.

And this matters, since the researchers found that on a monthly basis, about a third (35%) of the top 50 retailers’ audience comes exclusively from smartphones and tablets.

Translated, this means that of overall U.S. retailer website usage, retailers are facing more consumers viewing their sites only from a mobile device.

By retailer, some are seeing more mobile-only visitors as a percentage of all visits, but all are facing millions of them. Here’s the comScore breakdown by retailer of the number of mobile-only monthly visitors:

• Amazon sites – 43 million
• eBay – 22 million
• Walmart – 19 million
• Apple.com sites – 11 million
• Target – 14 million
• Best Buy sites – 10 million
• Ticketmaster – 9 million
• The Home Depot – 7 million
• Etsy.com – 6 million
• Lowe’s – 6 million

The key here is that it’s not only that more people are visiting retailer sites only via mobile device, but they also tend to view certain categories depending on which device they use.

For example, the leading categories visited by smartphone owners are books, healthcare and retail movies. This passes the logic test, as smartphone owners can easily search for a book on Amazon, scan a prescription label for a quick pharmacy renewal and rent or buy a movie.

For tablets, the most visited retail categories are home furnishings and apparel. This also rings true, with the ability to see more rich media on the larger tablet screen.

Over time, this will matter more, as the dollars moving into mobile commerce continue to rise.

During the first half of this year, mobile commerce spending reached $11 billion, according to the latest comScore figures. For the entire year, the research firm is looking for mobile commerce spending to pass $25 billion.

The larger spending opens the door for a much more segmented view of how mobile is impacting all of retail, one retailer and one category at a time.

Merchants may not yet totally comprehend all the evolving details of mobile shopping behavior, but a mobile device behavioral roadmap is beginning to take shape.