[Gandalf Parker]

Actually thats one of the big problems with digital distribution. More than with the mail system (at least in my country). Ive been involved in sites trying to come up with their own controls on digital download. Its still an ongoing effort across the net.

The larger the product the more likely it will not arrive quite intact. So the system has to handle the purchase thru credit cards or paypal, then authorize a download, then remember the authorization in case the download breaks, then be able to allow the download again in a way that does not support someone else downloading it. And it has to do that without directly tying in the purchase information (you dont want credit cards stored forever on a download server). Usually its done with multiple servers. A hefty expense.

The purchase system has been ironed out for quite awhile. There are "shopping cart" packages available for installing on a server. But there are no good packages yet for DD. And the sites which offer only DD for their produts are being closely watched by everyone else to see how effectively they can manage the problems.