I'm sorry, I have to disagree about micropayments. For most people (including people in finance), micropayments are anything less than 1 dollar. $0.25 is most definitely a micropayment. The reason is simple: with any payment processor, your per-transaction fee is something like $0.30 + 3% of the transaction. So a $0.30 sale nets you zero, because it's all taken up by the fee, and anything less than that will cost you money. For transactions under a few dollars, these fees are absolutely prohibitive.

So even for things worth a quarter, a real micropayment system would be a boon.

Now, the problem with things like Blendle, the iTunes store, etc., is that even with my definition of micropayments, they're not that useful, because they lock you into that vendor: you have to have an account with them, and you basically have a "tab" with them (much like going to a bar) that you build up, and eventually get billed for and pay all at once, so that they don't get socked with giant fees. This, obviously, only favors large players: Apple can afford to sell you $1 movies and songs this way, because it keeps you coming back to their store, but this doesn't help sellers who want to sell stuff on their own, outside of some giant player like that (who of course takes a gigantic cut of the proceeds for selling on their store).

A real micropayment system would let buyers and sellers exchange pennies at a time, with extremely low fees. PayPal got us a little closer to this by letting small sellers easily establish an account and get money from buyers (using their credit cards), without having to pay huge fees for a traditional merchant account. But PayPal gets socked with the same fees from Visa/MC as everyone and passes them on, so you still have to pay the same $0.30+3% per transaction. A micropayment system would have to bypass Visa/MC altogether. We'll never have micropayments, or lower fees of any kind, as long as we're stuck with the Visa/MC cartel.