I think easier payment methods could be a big part of the solution. Something like Apple's single-touch-to-pay should be available on all platforms and without the need to sign up, create username, choose password, confirm link in email, etc.

Currently the signup and payment flows are so long that they greatly reduce impulse buying. I really wouldn't mind paying 50 cents for an interesting article if there just was a simple button to click, but I'm not going through that annoying flow for an article.