Four senators sent Facebook a letter of "concern" over its privacy practices—and warned the social network that federal regulators would likely investigate the company. Congratulations, Facebook. It often takes decades to achieve this level of government scrutiny.

Microsoft was founded in 1975; it took nearly two decades before the Justice Department went after the software company on antitrust grounds. Started the same year, Apple Inc. avoided antitrust issues until last year. But Facebook's repeated and brazen rollbacks of users privacy have apparently touched a nerve; Democratic senators Charles Schumer, Michael Bennett, Al Franken and Mark Begich—the latter a member of the communications subcommitteesent the six-year-old startup a letter expressing concern over the new privacy rollback we've been writing about, including making data like likes, interests, hometown, education and current city public and allowing third-parties to store Facebook data indefinitely.

The senators called on the company to make this privacy rollback "opt-in" rather than "opt-out," since the latter process is "long and complicated." Then they said they "look forward to the FTC examining this issue," implying the FTC will indeed act on complaints over Facebook's prior privacy rollback.

Facebook's public policy spokesman Andrew Noyes said in an email:

"We appreciate the concerns raised by Sen. Schumer and expect that further dialogue with interested members of Congress about the user controls that accompany the tools announced by Facebook last week will alleviate any concerns they may have."

Translation: Hopefully we can keep the government off our backs at least a little while longer. But spoke like a real DC vet. Facebook's finally all grown up (sniffle).

[Image via deneyterrio's Flickr]