Google's not the only company to offer a new ad format today. Skype introduced its new Click & Call ads, supported by Marchex. Skype says Click & Call Advertising provides an efficient and measurable way to acquire new customers by using Skype to drive inbound calls.

With the program, advertisers can have their phone numbers highlighted with a blue "Free Call" button anywhere their number is displayed online. When a user clicks the button, they will launch the Skype software and call (at no cost to the caller).

"Working together with Marchex, our objective for Click & Call Advertising with Skype supported by Marchex is to deliver a performance advertising tool that turns the Web surfing behavior of Skype users into calls to advertisers," says Skype's Director of Advertising, Andy Sims. "Businesses will now have the opportunity to acquire potential new customers by using Skype in a highly efficient and measurable way. The experience is also beneficial for Skype users because it’s fast, convenient and the calls are free."

"We believe advertisers have a strong demand for generating inbound phone calls and Skype is a promising customer acquisition channel that offers a large base of users who are typically familiar with making calls from a PC," says Marchex COO Pete Christothoulou. "Today, we are seeing a shift in the way consumers find phone numbers, the way they place calls and how those calls are paid for. As a result, coupling Skype’s reach with Marchex’s call advertising technology, sales team and service, we believe we can offer a high quality solution to large and small advertisers."

Advertisers pay a fixed amount per call. Rates are determined based on advertiser categories.