When The New York Times launched its paywall last month, many analysts saw it as a bellwether for the rest of the newspaper industry, which is eager to find new revenue streams as print advertising dries up.

If it worked for the Times, others would follow.

Apparently the Times experiment is going well.

The word is that the San Francisco Chronicle is now mulling its own paywall, just days after the Tulsa (Okla.) World introduced one with similar pricing to the Times model.

But Hearst Corporation, owner of the Chronicle, does not plan to follow the metered plan set up by the Times, which allows users access to a small number of articles per month before the paywall kicks in.

Instead, according to the Bay Guardian, the Chronicle plans a so-called hard paywall that would require users to pay for each and every article.

By one account, subscribers would be charged $9.95 a month, as compared to the $15 the Times charges for four weeks of access. Presumably, access would be free to subscribers of the print edition of the paper.

There is no rollout date as of yet for the Chronicle paywall, but it's expected to debut along with a digital subscription plan for a new Chronicle iPad app, possibly by month's end.

The Chronicle has not confirmed any of this, and obviously a paywall would be a major and risky venture, coming years after users had gotten used to free access to the paper's online content.

The risk is that traffic would plunge dramatically, and that whatever subscription revenue came in would not be enough to offset the loss of online advertising revenue.

But the upside could be substantial.

Longtime readers could well decide to pay in sufficient numbers. And while site traffic would surely decline, what's left, that paying readership, would be that much more desirable to advertisers, so the paper could charge more to reach them.

Another possible upside would be that at least some online readers, faced with the paywall, would choose to resume buying the print edition of the paper.

Thus far most paywalls have remained experimental in nature. The Wall Street Journal is the only major U.S. paper with a longstanding paywall.

Last year Newsday introduced one, after which readership plummeted.

The Times wall has been in place barely a week and already there's a small but thriving community of readers dedicated to finding ways around the paywall. One such site was called NYT for a Nickel, but that's now out of business, forced by the paper to shut down.

Analysts now expect a slew of papers to follow the Times in erecting their own paywalls, testing all sorts of different pay formulas.

Close attention will be paid to the Times but also to the Chronicle and the World to see which of their plans, if any, produces the best results.

But the truth is that it will be many months before any of them will be able to claim success. The challenge is to retrain consumers, and that's reliably a protracted venture with always uncertain results.