It is also worth noting that most IPFS peers will cache content for some period of time even if not explicitly pinned. So if you site hits the top of Hacker New

It is also worth noting that most IPFS peers will cache content for some period of time even if not explicitly pinned. So if you site hits the top of Hacker News (and everyone was using a native IPFS browser) you would suddenly have thousands of peers with the content available. So in theory your one node can serve infinite users since once you serve one copy to the first user that user can replicate it to others. (The real world is of course more complicated but the idea works decently well in practice.)