This would be really interesting in combination with some zero knowledge proofs, so you can allocate your subscription fees to sites without the payment processor (or the site) knowing who you in particular are patronizing.
zcash's shielded pool is probably the closest to a solution for that that exists today, and at the very least a bunch of the cryptography/math/overall model should be re-usable in a more traditional setup.
(I remain basically a crypto skeptic but zcash appear to at least be -attempting- something focused and interesting enough for me to continue to pay vague attention)
