When you click on a subscriber-only item, a nice big box appears telling you it is only available to subscribers. While I like the subscription model you are developing, I thought I would mention that the only way to dismiss the dialog box is to add a month of premium subscription, or, reload/exit the web page.
It would be nice to have a cancel option as well - that would be an easier option than people trying to figure out they need to reload the page.
So far, I do like the concept and design.