After getting some bad press last year for holding money from several crowdfunding campaigns that had used the payment service, PayPal has finally published a list of clear guidelines. They govern not only direct campaigns using PayPal, but also crowdfunding services like Indiegogo that process some payments there.
While on the face the rules may appear a bit rigid, they are really about PayPal making sure they're not left holding the bag if promised goods are not delivered.
First PayPal wants to determine if the project is not illegal or just a pre-order vehicle. Then it requires that a disclaimer is posted saying that there is no guarantee of delivery. In some circumstances, individuals or organizations may need to submit additional information so that PayPal can verify their campaign. That's it.
Read the full list of rules and procedures here.