On Friday, Google AdWords announced a new method of targeting click-to-call campaigns named "call-only campaign."
The first to spot this, well before the announcement, as far as I know, was Kim Clinkunbroomer. She posted about it on her blog and on Google+.
In short, it gives advertisers a much faster way to target mobile devices that have a calling feature only. Google said:
Call-only campaigns are specially designed to only show on mobile devices that can make phone calls. This means every click you pay for can be a phone call to your business.
Ratan-Jha in an AdWords Help thread explained:
With call-only campaign you can have dedicated ad campaigns that target mobile devices, saying it more precisely, only those devices which have calling abilities. It means ads from such campaigns will not appear on devices like desktops or laptops.
He goes into a ton of details on when to and when not to use it.
The option is available when you set up a new campaign type:
Forum discussion at AdWords Help & Google+.
