Hi,
I had such an idea in the past - i am glad you have started this topic.
One of the most important features of PayPal is the guarantee you get when you use it. PayPal stands behind the people who pay with it and cancel transactions with no second thought. I was suffering from this as a seller, i used it few times as buyer. This is how eBay became so big - you can trust the system.
I think that there is a demand for such service with Bitcoin. I am quite sure that many people prefer to make business with unknown people via a trusted 3rd party.
The system itself is quite simple:
One of the parties start the transaction by simply creating it in the system:
- his email (we can provide email service based on Bitcoin address for complete anonymous transactions)
- other party email (or same email system, he will then give it to the other party and then he will be forced to change password)
- specific terms
- BTC address where they want the funds to be sent
- BTC address for cancellation of transaction
email is sent to both of them, they need to agree on the terms or modify it. Once both agreed, they will be given a Bitcoin address (our address) where they need to send the BTC.
Another email is then sent to both of them, asking to approve the transfer. This can be pending in the system for unlimited time, until they agree to release the funds.
When confirmed, funds are sent to the address they provided before agreement.
If all goes well, funds are released, we take commission.
If not agreed, they both need to provide explanations and agree on the resolution.
If not agreed on resolution, our stuff will try to mediate.
If no mediation was done, funds are released to the second address they provided. (this part needs a beter solution)
This is 12-18 days of work for a skilled programmer and needs few k$ for legal stuff (agreements, TOS, TOU etc).