Mobile internet usage is on the rise, with tablet shipments expected to exceed PC shipments in the coming months. Marketers looking to reach the growing mobile audience may be interested in Google's claim that its click-to-call ads are gaining rapid momentum.

Today, in a blog post, the company says that click-to-call ads on both search and the Google Display Network lead to millions of calls each month – just one year after the launch of this feature. Surojit Chatterjee, senior product manager of the Google Mobile ads team, says the company's advertising partners started seeing significant results with click-to-call ads within the first month of its launch.

The company claims mobile is still a relatively new marketing space, and new advertisers can still benefit from early adopters' advantage. In fact, this will be the subject of Google's upcoming Think Mobile event.

Perhaps part of the reason marketers will still stand to gain early advantages from click-to-call ads is Google's potential plans to further develop the feature. As Brafton has reported, Google recently acquired SayNow, a social voice company, and this may bring a social recommendation element to click-to-call advertising.