Hmmm. What are the core differences between the "Freemium" model and the subscription model? I'm most familiar with Club Penguin, which does allow non-paying

Hmmm. What are the core differences between the "Freemium" model and the subscription model? I'm most familiar with Club Penguin, which does allow non-paying a limited subset of the functionality, but I've always thought of it as a "subscription model" (as that is what I pay for my children....)