Readers will pay for content online so long as three conditions are met:

1 The content is worth paying for.
2 The price is low.
3 The transaction is easy.

There are some trade-offs within those criteria. If you have an overwhelming need for a particular channel of content — the Financial Times, say, or The Economist — then you will accept a relatively high price, and quite a lot of friction in the process of subscribing.

But for paid content to be the rule rather than the exception, publishers need to deliver on all three criteria at once.

Here’s how it can happen.

There’s no particular problem or mystery associated with providing content worth paying for. Publishers do it all the time. What’s amazing is how much good writing is currently available for free. For example, I’d certainly pay to read the NYR Blog, provided that the price was right and the transaction was easy.

Getting to the right price is more of an issue. Publishers think in terms of one-to-many relations with their readers, and price accordingly; but readers want a one-to-many relationship with publishers. Each publisher wants to sell one subscription to every reader for $60 a year; but each reader would much rather buy ten subscriptions to ten publications for $6 a year each.

The customer is always right. With much lower prices and much bigger volumes, everyone would be better off.

Frictionless purchasing is getting closer, but it’s not evenly distributed.

You have it once you get inside the closed systems of the Kindle and the iTunes store — and the effect of it is clear and liberating. You sample more, you buy more. To return to the case of the NYR Blog, I’m 90% sure I’d pay $1 a month to read that content, even if I had to go through PayPal to do so. But I’m 100% sure I’d pay $1 a month to read it if I was buying with a single click on my Kindle, and 90% sure I’d pay $2.

But how to make frictionless transactions for individual pieces of content outside the closed systems? We need the internet equivalent of a Metro Card (in London: an Oyster Card), which is to say, a pass that the reader can preload with so many prepaid page views — say 100 page views for $10 — and then use to access individual pieces of paid content on any participating publisher’s website.

When we can meet all three criteria — quality content, low pricing, frictionless purchasing — we can do for paid content what app stores have done for software. Remember when software in a box used to cost $100, and you might buy a couple of things a year that you really needed? Now it costs $1 and you buy it on impulse.

We’re going to get there, even if the prepaid pass takes — I would guess — another year or two to arrive and scale. For the past five years or so we’ve been in a golden age of free content. Now we’re moving into a golden age of paid content, and that’s going to be even better.