Time spent visiting retail Web sites on tablets and smartphones has eclipsed that of time spent shopping via the desktop. A combined 51% of time on retail sites took place on devices as of February (37% on smartphones, 14% on tablets) compared to 49% on PCs, according to a new study by mobile ad network Millennial Media and comScore. The desktop share is down from 84% in 2010. But comScore indicates that while time spent is shifting toward mobile, it’s helping extend the desktop audience by 45% as consumers that start on PCs continue their shopping experience across devices. So there’s a fair amount of overlap among platforms. Who’s shopping on mobile devices? More than half the U.S. audience is men (52%) and 48% women, with most in the 18 to 44 age range. Nearly half (48%) have an Android smartphone, and 45% own an iPhone. Tablet owners tend to skew more affluent, with more than half with household incomes higher than $75,000, and 47% access retail content. Get the full story at MediaPost