I was advised to move this question to Development.
If a cryptocurrency and its wallet clients gave the user the ability to easily "lock" coins--making them unspendable until the original buyer unlocked them, would that reduce scamming? When you spend bitcoins, they're lost forever, even if the seller was a scam artist. People paid a lot for everything from mining rigs to altcoins, only to get shafted. If coins could be spent "locked" for a time, the seller would be holding the coins, but be unable to spend them on anything.
Leaving the coins locked, the buyer can't get his coins back under the circumstances, but he can at least prevent the scammers and others from profiting. Ethereum is building a Touring-complete language into their coin.
I had been thinking that there may be a simpler, more newb-friendly way to build auto-escrow into an altcoin or bitcoin protocol. (Bitcoin also has an extra bit and the ability to add some functionality to it in a similar way.) Still, a simpler approach would just be allow an optional trigger for a transaction. When you go to buy something, you plug in the number of bitcoins/altcoins to Spend (rather than simply "Send"), and the wallet sends a signal to the seller that that many coins have been reserved for the transaction. Instead of locking the coins, the wallet browser could be set to watch for a transfer or some change in condition (an amount of time, transfer of altcoins, elapsing of a charge-back period, arrival of a package with a set shipping number from UPS or FedEx, etc) that could be monitored simply by looking at changing info on the Web. The seller might even send along a short script that one copy-pastes into the Label field. Just check one or two boxes, then select a trigger from the pull down menu, paste a url into one field, and perhaps even a tracking number into another field. Then hit Send, and the payment will proceed perhaps when the delivery servicer picks up the package, for example.
That way, an auto-escrow feature would be intuitive, easy to use, and gain better adoption. Exchanges and sellers of bitcoins/altcoins could sell them confident that they are not going to get scammed on the chargeback.
Did I get everything?
Take a look at Bitrated, which facilitates doing the kind of thing you're trying to do using standard Bitcoin transactions:
https://www.bitrated.com/They do this with a third person involved as arbitrator in case the two parties disagree. In some situations you could survive with just the buyer and the seller, but that doesn't work with a completely anonymous buyer who doesn't care about reputation because they can refuse to complete the payment even if the goods are delivered unless the seller gives them a discount. (There are further potential twists to mitigate this, but it starts to get complex.)
This stuff has been usable in bitcoin for a while, but it's not trivial to create a user interface that makes the whole process simple enough for wide-spread adoption, and there's a chicken-and-egg problem getting both the buyer and the seller on the same page.
