Of course you've heard some version of this tale before. Winston Churchill says to a woman at a party, "Madam, would you sleep with me for 5 million pounds?"

The woman stammers: "My goodness, Mr. Churchill. Well, yes, I suppose . . . "

Churchill interrupts: "Would you sleep with me for five pounds?"

The woman responds immediately: "What? Of course not! What kind of woman do you think I am?!"

To which the British bulldog replies: "Madam, we've already established that. Now we are haggling about the price."

The story comes to mind upon hearing the news that the New York Public Library has gotten into the porn business. "With adults, anything that you can get on the Internet, you can legally get on a computer in the library," explained an official. "It's difficult, but we err on the side of free and open access."

What does this have to do with the Churchill story? Well, imagine you went to your local library in, say, 1989--or some other year before Al Gore invented the Internet.

Then imagine going up to the librarian and asking him, "Do you carry Hustler?"

The shocked librarian answers, "No."

"Back issues of Swank? High Society? Penthouse?"

"No, no, and no," quoth the librarian.

"Okay, okay, I get it. Do you have movies?"

The librarian answers: "Yes, of course."

"Great!" you reply. "I'd like to sign out the VHS of Debbie Does Dallas."

"What? No!"

"How about On Golden Blonde?"

Finally, the librarian explodes: "Sir, we do not carry any pornography. What do you think we do here?"

Well, the answer to that question is suddenly in doubt. Because up until very, very recently, the idea that public libraries should--nay, must!--peddle unfettered access to hardcore porn would have baffled almost everyone.

I'm hardly an anti-porn crusader, but the list of reasons why libraries didn't--and shouldn't--carry porn is vast. The two most obvious and mutually reinforcing reasons are moralistic and budgetary: (a) "It's wrong," and (b) "We have very limited resources and we must choose what we think is worthwhile and what has no redeeming value."

The problem is that the legs have been knocked out from under both answers. Of course, the moralistic--or "judgmental"--bias against porn has been eroding for generations. How bad or good a development that is depends on your point of view.

But until the Internet, it didn't matter. Sure, Playboy might make it through, "for the articles." But not even the most radical or deranged librarian could ever justify subscribing to Juggs over National Geographic, because in a world of limited resources, prudential editing is not merely valuable, it's unavoidable.

The Internet changed all that. The marginal cost of obtaining pornographic materials in libraries, once prohibitively high, is now nearly nonexistent. In fact, it's actually cheaper just to let it all flood in. Who wants to deal with the filters, blockers, and monitors? Just proclaim that the First Amendment requires unfettered access to porn.

But, again, just imagine that there was no Internet, and that all two-dimensional smut was still on paper, celluloid, or magnetic tape. Now imagine trying to argue before a cash-strapped city council that the local public library must not only provide some porn--free of charge!--to the public, but that it must provide mountains of it free of charge to the public, all because the First Amendment says so.

You'd be laughed out of the room.

Did the First Amendment change with the invention of the Internet? Of course not. What changed is that librarians lost both the "scarce resources" excuse and the backbone to invoke any other rationale--decency, child welfare, hygiene, safety, etc.--for barring porn from public libraries.

Technological progress poses such challenges. Don't get me wrong: I love technological progress. But technology makes life easier, and when life is easier, it's harder to stick to the rules that were once essential to getting by in life.

The list of customs and values that were formed or informed by material necessity is too long to contemplate because it includes nearly all of them. Cultures, like cuisines, are formed as much by what isn't available as by what is. Scarcity of meat is the mother of good seasoning.

The Internet doesn't completely eliminate scarcity of porn (or of hilarious kitten videos), but it gets us closer than humanity has ever been before. When scarcity drops, so does the price. And it seems that for the New York Public Library, like the lady in the Churchill story, price was always the issue.