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:
Ratan-Jha in an AdWords Help thread explained:
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+.