Google announced that it is making mobile site optimization a new factor of ad quality for AdWords campaigns that are driving mobile search traffic.

Google began limiting ad serving on high-end mobile devices when landing pages contained Flash-heavy content last year. Now, Google is taking the mobile user experience up a notch.

There are plenty of non-AdWords reasons to offer a good mobile experience, particularly as more and more people are using their mobile devices as a major Internet access point, if not their main Internet access point. Sooner or later it’s going to get to the point where it’s just as critical to have a mobile-optimized site as a desktop-optimized site, if that point isn’t already here.

“The best consumer experiences on mobile devices happen on websites that are designed for mobile,” says Google Mobile Ads Product Manager David Nachum. “We all know the difference that sites designed for mobile make in pure usability – they are designed for the smaller touchscreen, making it easy to find what you are looking for and interact with. We believe that giving consumers the best possible experience on their mobile device is critically important. A poor mobile web experience can negatively shape a consumer’s opinion of a brand or company and make it hard for them to engage or make a purchase. A recent study which asked users about the performance of mobile websites found that 61% of users# are unlikely to return to a website that they had trouble accessing from their phone.”

To make a long story short, if your AdWords landing pages are optimized for mobile, they will perform better, and “generally drive more mobile traffic at a lower cost” according to Nachum.

If you need a little help in getting optimized for mobile, he points to a free tool Google recently launched that helps you create mobile pages in Google Sites.

There is also a webinar about best practices for mobile sites.