There has been an ongoing dialog (see Om Malik’s Guessing Google’s VoIP Plan, for instance) in the blogosphere on Google Talk’s business model (and Microsoft’s for their new Teleo acquisition). The current favorite theory is that it will be a pay-per-call system attached to search. Click-to-call enabled advertisements — a replacement for the yellow pages. Aswath Rao points out that Skype already has this capability, and states that there is no money in this model. Indeed, Stuart Henshall over on the Skype Journal recommends that every business get a Skype ID, and use call forwarding to forward the incoming call to various people in the office — the VoIP equivalent of an in-bound 800 number customer service center.
I’m not sure I believe, as Aswath does, that there is no money in pay-per-click advertising linked to pay-per-call VoIP. It seems logical to me that:
A click through / call through event would be more valuable to an advertiser than a simple click through. Advertisers might be willing to pay a premium for this.
Mobile click through / call through might be even more valuable. "I’d like to eat at a chinese restaurant. Can you help me make a reservation?"
Advertisers might also be willing to pick up the cost of the PSTN leg, if they’re not already VoIP enabled, allowing Google to perhaps build a PSTN interconnect network on the backs of their advertisers, and maybe even provide free PSTN interconnect to Google Talk customers.