Hoping to administer a powerful sockdolager to online fraudsters, the California legislature passed a bill earlier this month that makes it illegal to impersonate someone else online.

Its backer, state senator Joe Simitian (D-Palo Alto), says that the old laws against fraud or defamation just aren't cutting it anymore. "In the age of the Internet, pretending to be someone else is as easy as using their name to create a new e-mail account. When that is done to cause harm, folks need a law on the books they can turn to," he said. "New laws are needed to crack down on this form of harassment."

California already has such a law, but it dates to 1872 and only covers faking someone's signature. The new bill extends the principle to Twitter, Facebook, and e-mail, and it makes "e-personation" (yes, we're groaning, too) a misdemeanor punishable by up to $1,000 in fines and a year in jail.

The bill's text is brief. In an effort to carve out freedom of speech exceptions, the bill outlaws only "credible" impersonations, and the impersonation must be done "for purposes of harming, intimidating, threatening, or defrauding another person." Fake Steve Jobs should be OK, but "harm" is a fairly nebulous standard.

The Electronic Frontier Foundation sees obvious potential for abuse here as corporations target those who might seek to parody their actions or impersonate them as a political gesture—in other words, the Yes Men. The Men (and presumably, some women) have pulled off a couple of terrific events in recent years, including one last year where they impersonated the US Chamber of Commerce, rented the National Press Club, and issued a major announcement reversing their current global warming policies.

The hoax fooled a number of real reporters, garnered tons of attention, and ended in bizarre fashion when an actual Chamber of Commerce employee showed up and tried to shut down the whole proceeding. The Chamber eventually sued the group.

Could similar online events be illegal under the new bill? Should they be? "Temporarily 'impersonating' corporations and public officials has become an important and powerful form of political activism, especially online," says EFF today. "Unfortunately, the targets of the criticism, like the Chamber, have responded with improper legal threats and lawsuits. It would be a shame if Senator Simitian’s bill added another tool to their anti-speech arsenal."

As for the issue of "credible" interpretations, EFF says "that argument misses the point—identity correction depends on initial credibility, just as it also depends on prompt exposure."

The bill awaits Governor Schwarzenegger's signature. EFF encourages him not to sign.