That's a great point, bigian. FWIW that's not a PayPal-specific policy - Visa and MasterCard's TOS explicitly state that you cannot bill the credit card until the merchandise has shipped.
True, but I don't hear nearly so many horror stories about Visa/MasterCard choosing to keep all the money people think they have given you for 180 days (exactly as you agreed they could when you signed up) while they "investigate".
I also hear regular reports of businesses which perhaps should have chosen their payment processor more carefully given the nature of their business, who clearly have a product which doesn't get "shipped" in any way that could comply with that policy - I think a European Ruby conference was the most recent one I've seen discussed here, how should a conference organizer manage their bookings to comply with this sort of policy? He'll, even Burningman got burnt by their ticket seller a year or two back "we're just gonna hang on to a few million dollars worth of ticket sales money, because your annual event that's been running successfully for ~20 years now with ~50,000 people a year recently - it might all be a big fraud!"... Unfortunately, choosing to sign up with PayPal means explicitly agreeing to allow them to do exactly that with very little recourse - and it's not necessarily _wrong_ - PayPals business is basically built on betting they can do a better job of fraud prevention than e banks/credit card companies are doing, and offer payment services to more people than the banks will and earn money from people the banks consider "too high risk". This allows then to provide a service that let's people like the OP go from idea to fully functional ecommerce website in 4 hours, but it also means you're giving them rights to retain "your" money to cover any fraud risk they might consider you to expose them too.
Its not a wrong/bad policy of PayPals, but it's a policy that I've seen many people not realize they were signing up for.