It's only mid-January, but the year of paid online content experiments appears to have arrived quickly. The strategy, logistics, and metrics of success remain sketchy, but I think I see the beginning of a consensus: an online pay wall should be not too high, not too porous, but just right for preserving light traffic while persuading heavy users to become buyers.

Three recent developments support this view.

First, the Dallas Morning News introduced a redesigned site Monday morning and will let registered users browse at will until asking for money starting Feb. 14.  Protected content is marked with an icon, so during the month's trial run you can gauge what you will be getting or losing depending on whether you decide to pay up. Print newspaper subscribers get free access.

Moroney told the Nieman Journalism Lab earlier this month that $16.95 will buy unlimited access to the website and related mobile and tablet apps (though details remain to be filled in on the apps).

Moroney wrote his staff to be prepared to "be vilified" by free content proponents of various stripes. I picked up some of that hostility browsing the site, where considerably less than half the stories were the sort of enterprise or commentary targeted to go behind  the pay wall.

Under an analysis of Cowboys coaching changes in process, the first commenter wrote:

Really? We're supposed to start paying for what is good Cowboy info, but by no means exceptional. ESPN's Cowboy site is, at the very least, equally good if not better. And it's FREE!!!
You guys at DMN are cutting off your nose to spite your face. Very bad Public Relations move. We'll see how many people sign up and pay for this.

Of course, the price will be for all protected articles on a range of topics, not a single piece. But as Moroney has acknowledged, it will be a tough sell and may not succeed.

I also learned last week via a call from an AP reporter that Hawaii Civil Beat, the site edited by John Temple and bankrolled by Pierre Omidyar, has punched a few new holes in its $19.95-a-month paywall.

As I highlighted in a post late last year, Civil Beat has been offering a variety of discounted, get-acquainted offers since its launch in May. Now infrequent or new visitors will have access to an unspecified number of articles before being asked to pay anything.  Sharing links to individual articles will also be free.

Those who have followed The New York Times' extended run-up to the launch of its metered model later this winter will recall that at this late date, the Times is still not saying how many articles per month will be allowed for free.

Executives have also suggested that the unspecified monthly access rate will be adjusted strategically.

Civil Beat goes one better at playing its cards close to the chest, declining to say how many articles will trigger a pay request. That will be determined by a proprietary algorithm.

Finally, The New York Times reports on a "study" from Journalism Online, indicating that several small sites using its version of the metered model have declared very modest losses in unique visitors and in page views and no losses in advertising.

As a Jay Rosen tweet and a CJR critique of The New York Times piece point out, the study is promotional in intent and extremely vague on details.

The big questions -- revenue generated from the pay wall or print circulation preserved by taking away the read-it-for-free options -- are not discussed.

My hunch is that we will be deep into the year of experiments  before any information is forthcoming on those key metrics -- or on whether time-on-site and value to advertisers falls as many heavy users decline to pay.

I think it is noteworthy that the Dallas Morning News and the Boston Globe (which plans to introduce its version of premium paid content later this year) are among the most expensive metro papers for print subscribers.

The bigger the gap between paid and free access, the more it seems wrong in principle to give away an unlimited ration of expensive-to-produce journalism.

Plus, there are substantial circulation revenues being lost -- and bigger losses to come in the future -- each time a frugal reader opts out of pay-for-print into free online.