Rumors last week that Google were paying carriers a portion of their revenue on in-application advertising have been strongly denied by the company, who insist that only Google search ad revenue is shared with network operators.  The rumors had been used by some as evidence for the recent proliferation of Android devices offered by carriers, but according to an official comment given to eWeek, it has no basis in fact.

"We share revenue on search, not on mobile applications. The same is true for non-Android devices that use Google as the default search engine" Google spokesperson

Carrier AT&T in the US is notable for having exchanged Google search functionality for Yahoo! on handsets like the Motorola BACKFLIP.  Google has previously said that OEMs are free to load builds of Android with their own choice of search provider, though it can then limit what Google-brand apps (such as GMail) are also preinstalled onto the handset. Specific details of Google's search ad-revenue share deals with carriers are unknown at present.