What's happening here is that it's not just "free access with ads or pay for access." It's "free access if you came from google, so that google can index our pa

What's happening here is that it's not just "free access with ads or pay for access." It's "free access if you came from google, so that google can index our pages, but otherwise pay for access so that we can put the same content behind a paywall." It's less a business model and more an SEO trick that Google puts up with under certain conditions.