Making a more legal P2P program?

Question

I hear alot of bad stuff on peer to peer programs. A couple of my friends use it to check out stuff before they buy it (mostly comics and anime toons they are interested in, so they look at it and buy the real version if they liked it). Which is somewhat the reason why other people who download the stuff do that, or just to get free stuff.

Anyways what I don't get is if there was a service which was more legal so that the product isnt permanantly taken/saved, so that a person got to check it out without having to buy it, yet doesnt get the choice to just keep it permanantly. Also maybe be able to order the product using this program.

basically here is my vision of it
-open it up, browse around, and download the movie, music, etc.
- the file it is on doesnt allow copying, changing, burning, etc.
- no 3rd party programs alllowed to be made
- once file is downloaded, it can be experianced a certain amount of times (play the file 3 times) or locks after some number of days. Just like sharewares that last for 30 days. Make a movie last for 2 or 3 days.
- then user or the program deletes the file, maybe keeps a log of previously downloaded files etc.
- Then have a cart option and be able to send for the item online or be told what retailers sell it.

Answer 1

The problem then is... How do you get people to accept this new service, when they can get the "real thing" on that "other" service?

And if the author/publisher choose NOT to give you a preview, then what will you do?

Amazon already lets you preview many of the books in print and order online.