Google's paid search clicks from mobile devices increased by 132% in 2011

"In 2011, paid search clicks from mobile devices on Google increased 132% from January to December. By December 2012, Marin Software projects smart mobile devices will generate 25% of all paid-search clicks on Google as a result of the explosive adoption of smartphones and tablets. Consumers are much more engaged with search ads on smartphones and tablets as opposed to desktops, as evidenced by click through rates that are respectively 72% and 31% higher. Search ads on smart mobile devices also have a lower costs-per-click than desktop ads. This difference, in cost coupled with higher click-through rates on mobile, creates favorable performance conditions for advertisers and increased demand for mobile ads."
Source: Press release from Marin Software, 26th March 2012