Google is changing its rankings to favor websites that are friendly to mobile devices, the search-engine leader recently announced.

http://googlewebmastercentral.blogspot.com/2013/06/changes-in-rankings-of-smartphone_11.html

The flip side of that is that websites that aren't friendly to smartphones and tablets risk sliding down the search-engine rankings. No matter how rich, sparkling and invofrmative the content on a website, the website will suffer a penalty if the content isn't optimized on a mobile device. That website will also be penalized if it's not built to steer mobile users to the right page, or if the website commits any of a host of other errors.
 
https://developers.google.com/webmasters/smartphone-sites/common-mistakes

"To improve the search experience for smartphone users and address their pain points, we plan to roll out several ranking changes in the near future that address sites that are misconfigured for smartphone users," Google wrote on its website.

Of course, websites with those faults were already penalizing themselves. If a website is garbled on a smartphone, people aren't seeing its content. If tablet users are getting redirected from the page they want, they'll eventually give up.

It's just that now Google will lay an additional penalty on top, one that can make a website less prominent even for traditional Internet surfers.

Particularly troubling for websites that aren't mobile-friendly is that this comes at a time when mobile ecommerce is booming -- at a time mobile devices are revolutionizing ecommerce.

Mobile Ecommerce is Booming

http://www.essent.com/News/Blog/Mobile-devices-drive-Search-Engine-Marketing-surge-and-Essent-has-the-tools-to-take-advantage.htm

Mobile Devices are Revolutionizing Ecommerce

http://www.ibtimes.com/mobile-devices-are-changing-ecommerce-heres-how-1297265#

Essent SiteBuilder addresses these issues by providing integrated browser identification, automatic routing to device-specific pages, and content formated for various form-factors including mobile and tablet devices.