Predicting what lawmakers will do isn't a science, but when two of the biggest companies in a given industry offer the same advice, the rest of the field should take note.

Testifying before a Senate Commerce Committee hearing on privacy and online advertising, representatives from Google and Microsoft urged lawmakers to come up with some basic privacy protection for consumers online.

According to a CNN report, both Google and Microsoft agreed that basic protections should be based on three core principles: Consumers should be clearly notified as to what data is being collected; consumers should be able to control how that data is used; and that data should be secured to keep it from falling into the wrong hands.

But that call for regulation hasn't gone down well with many in the industry, especially Randall Rothenberg, president of the IAB, who told The New York Times that "our industry is under a regulatory threat in Washington."

The hearings, which began yesterday, also highlighted the complexity of regulating such a decentralized industry. While Congressional lawmakers have the power to set standards for online privacy, another branch of government, The Federal Trade Commission, is in the process of working toward industry self-regulation.

Lydia Parnes, director of the FTC's bureau of consumer protection, told lawmakers that self-regulation is the best approach to foster online growth and help keep much of the internet's content free.

But Leslie Harris, CEO of the Center for Democracy & Technology, a privacy advocacy group, said self-regulation is "not the whole answer."