The guy who wrote that the American frontier closed more than 100 years ago -- he's a five-star moron. The frontier's still wide open. We just changed its name to the Internet. Maybe the most freewheeling territory in cyberspace is consumer-review Web sites such as Yelp, where customers rate sushi joints and endodontists and churches.

Sometimes they post assessments as dry and sober as a temperance newsletter. Sometimes they try to channel Jonathan Gold, like the laconic diner who wrote of my favorite pizza hangout, "It's good pizza ... don't expect to be born again or anything." And sometimes they bring knives and guns. A foodie slagged the chef at an Italian restaurant in Vegas as a "ghetto guido."

The push-back was inevitable. A recent nudge came from the San Francisco Bay Area. On Yelp, a man detailed a billing dispute with his chiropractor, then concluded that he'd found a "better, honest chiropractor." His first chiropractor asked the patient to remove the review for "unjustly" characterizing him as "unethical and dishonest." The patient refused, the chiropractor got a lawyer, the patient did take down the post, but the chiropractor sued anyway.

Since then, a Bay Area dentist sued a couple over their Yelp slam of her treatment of their son. This time, Yelp itself took down the post. On the East Coast, drugmakers in an investor lawsuit want to bar comments on a site called CafePharma. The site, so the lawyers say, is "literally the cyberspace equivalent of scrawls left on a men's-room wall."

Here's the deal with the Wild West frontier, then and now: You're on your own. No sheriff, no "big media" filter to protect you, not even from yourself.

The Communications Decency Act of 1996 effectively took most Web site operators off the hook. The act says Web sites aren't publishers and are not responsible for what people put on their sites, which is why the chiropractor didn't sue Yelp.

Thomas R. Burke is a First Amendment lawyer in San Francisco. "People routinely write comments online that they'd never dare say in person," he said, "but that doesn't make them any less protected under the First Amendment. Expressions of opinion are protected, and, ironically, the more 'over the top' the comment, the more it may be protected as opinion."

Opinion is free speech, but there are legal limits even to that, and not just shouting "fire" in a theater that isn't aflame. It may have been "the worst meal" you ever had -- but post, "This restaurant is so bad, I know it's a front for criminal money-laundering," and that's heading toward libel (unless it's true), and you may hear from a lawyer.

The waters just got deeper. The grass-roots consumer-rating operation the Zagat Survey has agreed to work with insurer WellPoint Inc. to let consumers rate doctors.

Dr. Dev GnanaDev loves Zagat -- wouldn't dine without it -- but as head of the California Medical Association, he thinks it's a terrible way to evaluate doctors. "It's basically a complaint form," not an informed analysis of care, he said. And if it's driven by vox populi on medical peripherals -- how old the waiting-room magazines are or how good the parking is -- you could wind up not with the best physician but with "American Idol, M.D."

The chiropractor-versus-reviewer lawsuit was settled out of court, which is a shame because we need public precedents to give us a legal compass on all this. Andrew Keen's "The Cult of the Amateur" made him the scold of cyberspace culture. Said Keen: "I think it's very healthy that this person is being sued. I think people have to be accountable, and the Internet is where most people think they can say anything and not be accountable or responsible." To enforce accountability, there is "no other alternative apart from the law courts."

As that implies, Keen is in favor of a substantive remedy. Shouldn't the Internet self-correct before government big-footers step on freebooters' cyberspace? I asked meekly. Keen bristled: "I don't see anything wrong with regulation. We have regulation in other avenues of society.

"The Internet is just another kind of society, and societies all operate under rights and responsibilities; Internet people operate purely on the basis of rights without responsibility."

Take away the anonymity of the Internet, he says, and "a lot of the other problems would fall into place."

So maybe I should take back that thing I said about Frederick Jackson Turner being a moron for saying the frontier is gone. Maybe even the cyberspace version will disappear.

But I don't have to give up my dream of being a tough, edgy Internet poster yet. "Paper Shredder" -- it's a persona that's everything I've always wanted to be: bold, slashing -- and anonymous.

Morrison is a Los Angeles Times columnist and host of a daily public-affairs show on Los Angeles public radio.

(March 1, 2009)