> My understanding is that if you don't wait for multiple confirmations, then it's not particularly challenging to double spend bitcoins. That's incorrect, the

> My understanding is that if you don't wait for multiple confirmations, then it's not particularly challenging to double spend bitcoins. That's incorrect, there is a significant cost associated with executing a double-spend attack. For small transactions, it's uneconomical to mine an alternate chain in order to execute a double-spend attack. If you trust the miner a little bit, you can assume that a zero-confirmation transaction be part of the common blockchain. Now it's not advisable to do that when selling somebody a Ferrari and letting them drive off, but it's probably less risky than accepting a credit card payment. Regarding reputation: I don't quite understand the point. You'd just have to sign your tx with a private key that has a corresponding public key with some reputation attached to it. This is pretty independent of bitcoin itself. You could even build a system where you deposit some amount with a third party (or multiple third parties using a MULTISIG tx), which will reimburse the vendor with that amount if a double spend is executed.