The New York Times paywall is here, and it’s about time. Don’t ask me why it took so long and why it cost $40 million to build, the point is after a decade and a half of giving away its expensive journalism online, the Times is saying it’s worth something: Pay us, please.

The straw man argument against paywalls has always been that they’ll drive readers to start reading other free sites. Rupert Murdoch actually, foolishly, did that with the Times of London.

But the modern paywall isn’t a you-pay-or-you-don’t-read proposition. The Wall Street Journal, which was the smartest of all the papers and charged online all along, has more than a million online subscribers. For most of its fifteen years, the WSJ paywall was high. A few years ago, it started loosening up to try to attract scavenger web traffic—folks who pop in on a link from Drudge or via Google search here and there. It’s not worth much, but it’s worth something. Online subscriptions are still growing. The Journal is having its cake and eating it, too.

The Financial Times has a pay meter—you get X amount of stories a month before you run into the wall. It also has a Google workaround, which I use, that lets you read five stories a day for free if you come to the via search.

These are leaky paywalls, designed to get money from the 5 percent or 10 percent of your readers who make up a whopping share of pageviews and thus ad revenue, anyway, while allowing non-loyal readers to still give you your digital pennies and nickles from their visits.

The Times’s more closely resembles the FT’s. You’ll get twenty stories a month before you’re asked to pay your $15 a month. Incoming links from blogs, Twitter, Facebook, and the like won’t count toward that twenty stories, so the Times should still get traffic from those sources.

I suspect twenty free stories is too high, particularly when combined with the porous backdoor from social media. But it’s better to start off high and then gradually adjust it as the data comes in and you see what the effect is. And that’s a key thing to remember here: This is just a start. The details of the Times’s paywall this time next year will probably be a lot different than at startup. Expect the twenty free stories number to drop, for one. I think the multi-platform cost is way too high, too. It’s $15 for the Web, but $35 if you want to read the paper on your phone and iPad. I suspect that $35 will be closer to $15 than anything by six months or a year from now. The Times was smarter in giving print subscribers free access to all digital platforms. That will help preserve print circulation for those of us who are heavy hybrid readers.

The problem the Times and all other newspapers and magazines are facing is that, as readers increasingly move online, news organizations aren’t getting enough money from them to maintain newsrooms of any decent size. Print subscribers and advertisers heavily subsidize the free news that online readers take for granted.

But those print subscribers are falling away, in part because why buy the cow when you can get the milk for free? The Times paywall will not only add incremental online subscription revenue, it will give print subscribers another reason to keep paying their $700-plus a year. It’s a simple theory: If you charge online, your print circulation will decline less rapidly. Now that it will be getting online subscribers, expect those dismal Times circulation numbers of recent years to head into positive territory. Watch the first full Audit Bureau of Circulations numbers to include the paywall’s effect. I’ll bet you a dollar it shows the Times’s circ swinging from a big loss to a decent gain.

The Times will also get a small number of people who will be happy to pay online because they see it as something of a civic duty. And it is. If you think The New York Times is an essential institution, and it is, you now have a way to show your support, sort of like how listeners send money to NPR and PBS (one can dream that the Sulzbergers would take the NYT nonprofit). This won’t be a million people or anything, but I’ll bet there are more than you might think.

The Times, by the last estimate I saw, pays upwards of $200 million a year just for its newsroom. It gets somewhere between $100 million and $150 million a year in online advertising, and that’s surely inflated artificially by so-called upsells.

Ryan Chittum is a former Wall Street Journal reporter, and deputy editor of The Audit, CJR's business section. If you see notable business journalism, give him a heads-up at Follow him on Twitter at @ryanchittum.