i imagine at some point we will have applications (or operating systems) that do the work of subscriptions for other applications. we will subscribe to addresses, and individually assign each subscription an interval to wait between reloads. when new content arrives, it will be automatically sent out to applications that can handle it. new events will be sent to our calendars, new music will be sent to our music applications, new photos will be sent to our photo applications, and new web content will be sent to applications that will look a lot like modern news readers, only without the subscriptions. the usefulness of subscriptions is general enough that i already have multiple unrelated applications using it. these applications would be easier to develop if the work of subscriptions was already done, which would result in better software for users.