The opportunity is to *replace* dwolla with a service that keeps its word. All they are is a webite using the ACH system. Pretty simple stuff really.
Dwolla is kind of misrepresenting what they can do if they advertise non-reversible transactions and use ACH.
Federal law requires banks to make funds available from reasonably sized deposits within three days, but the interbank clearing period is 14 days, after which, absent extreme circumstances, the transaction can no longer be reversed.
We're all familiar with the scam where a Nigerian sends someone a "Cashier's Check" and tells them to deposit it and wait for it to "clear", and then wire them a percentage of the money. They wire funds from their account, only to find a large negative balance a week later .
It's not unreasonable for Dwolla to uncredit funds where a bank transfer to them is later reversed. It is unreasonable for them to advertise the transaction as "final" before they have "good funds" from the person sending the money.
This is a case, as the old saying goes, of "the mouth writing a check the ass can't cash."