Ho trovato un sito americano che "noleggia" video, leggendo nelle sue faq dice che:
Most titles have a 7 day viewing period during which you can view the video an unlimited number of times. Your viewing period begins when you complete the transaction.

At the end of the viewing period, the file will remain on your hard disk but will not be playable. If you wish to continue viewing, you can return and renew your license or purchase a hard-copy DVD or VHS available on our site.
To protect the work of the many small, independent video producers who make their videos available on this site, videos will only play on the computer used to download the file. If the file is transferred to another machine, the file will not work on the new machine.
Dice poi che i MAC non supportano questa funzione e che windows media player è il videoplayer.

Ora credo che la cosa sia gestita da cookies e database.

Io vorrei fare una cosa del genere ma in asp sono una vera cippa mi date qualke indicazione?
dove cercare o come fare....grazie