As TechCrunch predicted, however, Apple is insisting that, for every subscription offer, customers have the choice of which way they want to buy it.

FORBES: Apple Introduces Subscriptions -- But There's a Catch

For example, if a student gets a subsidised subscription (as The Times used to offer) is this the same as a full price subscription for ad purposes?

FORBES: The Wall Street Journal Europe's Circulation Scandal

Special Offer: Click here for a 30-day free trial subscription to any investment newsletter available from Forbes.

FORBES: Reaching Bottom With Bernanke's Help

Only NetFlix and Amazon offer an all-you-can-eat subscription model for streaming, the rest are individual rentals.

FORBES: NetFlix: Opportunity to Buy or Bail?

Both units, for instance, are working with music labels to offer a paid subscription music-streaming service.

WSJ: Google Android Chief Andy Rubin Steps Aside

One solution might be to offer a variety of payment plans, to maximise the number of readers: eager ones might go for a subscription, while browsers might want to pay just for the occasional article.

ECONOMIST: So many ways to pay online