I agree completely. It's the genesis of "needing 48GB of RAM" that I'm curious about. The I/O issue with shared hosting, as I understood it, was that it took a long time to rebuild a busted RAID volume. This, to me, seems like a different symptom with the same underlying cause: there is a big server in the middle whose operation is critical to the site (otherwise, having 1 of N replicas take a long time to rebuild wouldn't be a big deal). For some sites, this big-server-in-the-middle is fundamentally necessary to do what the site does. I would like to know what it is about Pinboard that puts them in this boat. This is an honest question, not a sneaky way of saying "surely they don't need a server that big."

hint: You don't need 48gb ram to run a social bookmarking site.