PC World reports along with other outlets on the initiation of a Pay-Per-Call advertising feature dubbed "Click to Call" to compete with similar offerings from other online services. Examples of how this works can be found on Greg Yardley's weblog: a little green phone icon appears next to an AdWords item, which when clicked on pops up a place to enter your phone number with extra space for descriptive ad text. The on-screen presentation in the AdWords space then guides you to the completion of the connection. As noted in the new service's FAQ it's free to the user unless you're on a mobile and consuming on-air minutes. Details on pricing are not available, but PC World speculates that based on other services the prices are going to be in the $2-$30 per call range with $7 as a median. Yet another "Wow, this is huge" item from Google, to be sure, but all part of a more general growth in sophisticated ways to connect people with people through search engine marketing and other highly targeted content channels. Pay-per-call is still in its infancy, with tuning it for maximum lead quality still a concern, but there is indeed huge growth potential for voice and visual communication services to become the glue for completing a transaction. Just ask eBay, which paid big for online telephony service Skype. It's all about building the transaction - I trust, therefore I execute. And who better to trust than Google, many a user may say. The power of contextual endorsement from Google's core search content rides again...