• by Gavin O'Malley  @mp_gavin, January 28, 2016

While it’s easy to marvel at mobile’s ascent as the dominant shopping medium, the shift away from desktops is presenting real challenges for retailers.

Among other issues, mobile shoppers are browsing fewer pages per visit. In 2015, the average domestic desktop visitor checked out 8.3 pages per session, while the average smartphone user logged just 5.8 pages.

That’s according to fresh findings from SimilarWeb, which also found that the average domestic desktop shopper spent 6.54 minutes on a retail site, last year, which dropped to 4 minutes and 29 seconds on mobile devices.

“Engagement and time on site has not been maintained in the transition toward mobile shopping,” Pavel Tuchinsky, Digital Insights Manager at SimilarWeb, notes in a new report.

What’s the solution? According to Tuchinsky: “Retailers must continue to embrace the rapid change towards mobile, including better checkout flows, and integration between desktop and mobile sites.”

The rise of mobile commerce is clear. Smartphone shopping is now the default for U.S. shoppers with 55% of all Web site visits to retailers coming from mobile, last year.

On average, 55.8% of visits to all online retail sites in the U.S. came courtesy of mobile phones and tablets, last year -- compared to 44.2% for desktop. This reflected a further 2.62% increase for mobile’s market share in U.S. retail, last year.

During 2015, nine of the most popular 10 U.S retail sites, including Amazon, eBay and Walmart, all registered a bigger share of visits from mobile, compared to desktop visits.