In May of last year, Google canceled their call tracking feature intended for Google Audio Ads. But now, Google's bringing it back under the name of AdWords Call Metrics, a combination of Google Voice and AdWords.
Google's goal in this is to show advertisers that AdWords is more valuable than they realize, including driving offline traffic. The feature is available on PCs and high-functioning smartphones with full internet browsers.
For now, the Google AdWords Call Metrics will be a free service, but perhaps down the road a fee will be associated in a "pay-per-call" way. AdWords Call Metrics routes calls from the VoIP tracking number to a designated business number that Google is able to monitor. The metrics will capture the time and length of the call.
While access is currently limited, more and more people will be invited to see what its all about in the near future.