- pay before viewing: how do you know that the thing you're paying for is the thing that you're expecting? What if it's a rickroll or goatse?
- so do you give refunds a la steam?
- pay and adverts: double-dipping is very annoying
- pay and adverts: how do you know who you're paying? A page appears with a micropayment request, but how do you know you've not just paid the advertiser to view their ad?
- pay and frame: can you have multiple payees per displayed page? (this has good and bad ideas)
- pay and popups: it's going to be like those notification or app install modals, yet another annoyance for people to bounce off
- pay limits: contactless has a £30 limit here. Would you have the same payment system suitable for $.01 payments and $1000 payments? How easy is it to trick people into paying over the odds (see refunds)?
- pay and censors: who's excluded from the payment system? Why?
Essentially the problem with micropayments is microscams.