• by Wendy Davis , Staff Writer @wendyndavis, May 18, 2011

Among the array of privacy bills making their way through various state and federal legislatures is a California measure that would require social networking sites to follow new privacy rules.

The bill (SB 242) would prohibit Facebook and other social networking sites from publicizing users' addresses or phone numbers without their explicit consent. The measure also would require social sites to ask users to select their privacy settings when they sign up. Not surprisingly, Facebook, Google and other Web sites oppose the bill, arguing that it would hurt tech companies and is unconstitutional.

Their stance might be self-serving, but the measure likely is unconstitutional for several reasons. First, states can't regulate interstate commerce. That prohibition has been interpreted as preventing states from passing laws that would require companies to operate differently in different states.

Second, and perhaps more significantly, prohibiting sites from publishing truthful information raises troubling First Amendment issues -- particularly when that information consists of addresses, phone numbers or other publicly available data.

At the same time, it's understandable why lawmakers are considering this bill. Facebook has frustrated many observers by a series of seemingly endless, retroactive changes to its privacy settings. The result is that Web users who signed up for the site with one set of expectations about what will be public are blindsided again and again when the company changes its default settings.

Whether California's law passes or not, Facebook and other social networking sites should rethink their approach to privacy. Garnering users with one set of privacy protections, and then changing the rules after people come to rely on the service, is exactly the type of activity that encourages calls for new regulations.