As both a subscriber and a publisher, “continuous service” subscriptions make sense to me.
As a subscriber, it could mean the end of annual contracts: I start and stop a subscription anytime with a phone call or click of a mouse.
As a publisher, it could mean the redeployment of resources away from junk mail creation.
Industry practices and government regulations have made the annual subscription a circulation norm in the U.S. In Europe the continuous service subscription is the norm. It should be in the U.S., as well.