Jan 31, 2011 16:03 GMT  ·  By

Google is starting to seem some decent revenue from mobile ads now that smartphones are becoming widespread and the carriers can actually sustain a connection capable of delivering a proper web experience on the go. One ad unit in particular has been proving particularly popular, the Click to Call ads which add a phone number and the option to call the place or business with just one 'touch.'

Search Engine Land got some details from Google which is touting the success of the ad type which is doing so well that it's surprising even to Google, apparently.

The mobile space is still young and there's plenty of untapped potential for revenue. And making bets or estimates at this point can prove unreliable, there's no way to know for sure what works and what doesn't or what the next big thing may.

So its success may indeed be surprising even for the search company. Of course, Google may just propping up its products and highlighting one of its most interesting.

The ad units themselves are not that special, along with an URL or an address, Google enables users to simply 'click' on a phone number in ads. Google added the functionality to all businesses which provided a phone number.

It also charged advertisers the same as a regular click in a link, at least initially. It turns out that users found the added functionality very appealing.

Of course, you're most likely to place a call when you're with a phone in your hand. Also, if you're looking for something online on your phone, you're likely more involved than on a laptop for example.

"We’re seeing millions of calls every month; it has become a core part of a large number mobile search ad campaigns," Google’s Surojit Chatterjee told SEL.

Google wouldn't provide a more accurate number or says what it means in terms of revenue, but, apparently, it is becoming significant, taking into account that mobile ad revenue is still not even comparable with what Google makes on the regular web.