pinboard.in is always an interesting example. It started at a really low one-time sign-up fee, which grows as more users sign up: https://news.ycombinator.com/i

pinboard.in is always an interesting example. It started at a really low one-time sign-up fee, which grows as more users sign up: https://news.ycombinator.com/item?id=702914 https://news.ycombinator.com/item?id=702914. It used to be something like a dollar on launch. Wonder how it follows inflation, though.