A bitcoin-based escrow service.
Warning: Please be careful with your money. When sending money to an escrow partner you are trusting that the operator will not abscond with your funds and that the operator maintains secure systems that protect against theft -- internal or external. It is recommended that you obtain the real-world identity of the operator and ensure that sufficient recourse is available. Exchanging or storing significant amounts of funds others is not recommended.
Essentially, this service allows the payment recipient to know that the payment sender has delivered payment to an independent third party escrow. Funds are held by the escrow service until the payment sender releases the funds to the payment recipient.