particleman - 9:56 pm on Jun 25, 2013 (gmt 0)
While google is deprecating Checkout, Wallet does precisely what a mobile site needs. One touch checkout using existing payment info. The infographic even demonstrates it.
I'm not aware of a way to do this with apple/itunes accounts other than in app purchasing.
Mobile in my experience is something that is really really easy to get wrong. If your users are switching to the desktop site, then you probably don't have it right. Ideally it would present the same information in an easy to view way on a phone, but you'd be surprised how many sites get that wrong. I'm developing a new site right at this moment that is breaking some new ground in my niche as far as capabilities targeted at mobile and tablets. According to my traffic logs it simply needs to be done.