Facebook hired a prominent public relations firm to try to plant stories harshly criticizing Google's privacy practices. The efforts backfired when the firm approached a blogger who not only declined the assignment, but also went public with the exchange.

Rather than getting leading news outlets to circulate stories about privacy problems facing Google, Facebook has found itself having to answer questions about why it wanted to maintain secrecy.

Facebook says it never authorized or intended to run any smear campaign against Google. But it says it should have made it clear that it was behind the efforts.

Burson-Marsteller said Facebook had requested that its identity remain secret. The firm admits that violates its own policies.