How to lock distros so they can only be used on 1 URL?
I see 2 possible approaches (there might be others):


Include "something" that requires an API key, whereas 1 such key can be used on 1 URL only.
Offer a "hosted" version only, which uses your distribution. That way you don't have to ... "distribute" the distribution.


PS: Drupal is GPL, so before creating something that is based on Drupal, make sure you do understand the legal aspects of GPL ...