VOIP AND PAID SEARCH://The eBay-Google deal

The eBay/Google was widely covered, especially well in the New York Times. Going over the alliance after returning from my holiday, I noted some important aspects of the deal:

• It covers markets outside the US, presumably because Google is strong 'abroad' and US-partner Yahoo! has auction sites elsewhere in the world. And how about keeping both of them happy?
• Before anything happens, users must indicate which service they wish to use: Skype or Google Talk. Skype (proprietary) and Google Talk (SIP-based) will be made interoperable (but not for voice!). Will that work (and how long will this take)?
• It appears to be a call-back system: surfers enter their phone numbers and receive a call from the advertiser. (AOL uses the Ingenio system, that uses dedicated phone numbers in ads that users can click on.)
• Google (and Yahoo!) ads could conflict with seller interests. This takes some careful targeting, which is done by only allowing ads for complementary products. (Amazon does pretty much the same thing, by allowing ads from companies that don't sell items on Amazon.)
• Last but not least: neither sellers (who are too busy) nor buyers (Marktplaats recently ended the service) seem to be interested in using the service.