Facebook hired Burson-Marsteller to stir up concern over Google's privacy practices, the company confirmed Thursday.
The development highlights the rivalry between the two Internet giants and reveals how Facebook is trying to differentiate itself based on Google's reputation as inattentive to privacy concerns.
The contract came to light after a Burson executive emailed privacy researcher Chris Soghoian about writing an op-ed criticizing particular Google practices. Soghoian, who posted the exchange online, demanded to know which client Burson was representing, but the executive would not disclose.
A Facebook spokesman said Thursday that the company had sound reasons to raising awareness about Google's practices.
"We wanted third parties to verify that people did not approve of the collection and use of information from their accounts on Facebook and other services for inclusion in Google Social Circles, just as Facebook did not approve of use or collection for this purpose," the spokesman said.
"We engaged Burson-Marsteller to focus attention on this issue, using publicly available information that could be independently verified by any media organization or analyst. The issues are serious and we should have presented them in a serious and transparent way."
He added that "no 'smear' campaign was authorized or intended."