Robert_Charlton - 6:31 am on Oct 6, 2012 (gmt 0)

Actually, I am surprised, not by the potential, but by the actual number and how quickly it came. I'd researched this fairly recently, and came up with numerous sources that had the Marissa Mayer citing a figure of 20% as recently as late May, 2011. She says in a video here... [businessinsider.com...]

Marissa Mayer, cMay 26, 2011

Today, twenty-percent of the searches that are done on Google are done looking for local information.

In the article noted in the open post of this thread, Greg Sterling's postscript and the concluding graph provides clearer explanation of the jump...

Postscript: I asked Chitika to provide a breakdown of PC vs. mobile search in these findings. Chitika said that nearly three-quarters of Google’s local queries are in fact coming from mobile. It’s the opposite for Bing and Yahoo.

The graph shows 26% of Google local searches coming from PCs, with 74% coming from mobile devices.

And in our last month's Google serps update thread, "a huge shift" towards mobile was discussed around Sept 20, 2012, with many confirmations that the traffic was not just local traffic from mobile phones, but also B2B on "mobile ecommerce on tablets, not phones".

Google Updates and SERP Changes - September 2012
http://www.webmasterworld.com/google/4490381-14-30.htm [webmasterworld.com]

I don't think I've ever noticed so many such reports in one update thread. Sites that didn't have mobile versions were reporting lost traffic, and a high abandonment rate that could hurt them in Panda.