1) Site Subscriptions allow one to be notified of any new content or any major content changes to this site. This is the most convenient way of following a certain topic or a certain link or section. Take a simple photo album with many photos already inside it: if new photos are added to this album, a subscriber will automatically be notified through email of this latest content addition.
2) Site Subscriptions also allow one to gain access to Subscriber-Only contents. Subscriber-Only contents are published content that are categorized and restricted to site subscribers only. Unless you are a subscriber and has been authenticated as such, you will not have access to this Subscriber-Only content.
3) Site Subscriptions also allow one to gain access to Exclusive contents. Exclusive contents are published content that has been categorized and restricted to an individual subscriber or list of subscribers. This is a more granular access to content. As usual, you will need to be successfully authenticated before you gain access to Exclusive contents.
4) Site Subscriptions also allow one to Post Comments to site content where enabled.
How does it work? To answer that question, here is an overview of the process flow, starting from the Site Subscription Request. To the end user, it only takes 2 simple steps: the subscription request, and then the confirmation.