When we announced that RethinkDB is shutting down, I promised to write a post-mortem. I took some time to process the experience, and I can now write about it clearly.
In the HN discussion thread people proposed many reasons for why RethinkDB failed, from inexplicable perversity of human nature and clever machinations of MongoDB’s marketing people, to failure to build an experienced go-to-market team, to lack of numeric type support beyond 64-bit
float. I aggregated the comments into a list of proposed failure reasons here.
Some of these reasons have a ring of truth to them, but they’re symptoms rather than causes. For example, saying that we failed to monetize is tautological. It doesn’t illuminate the reasons for why we failed.
In hindsight, two things went wrong – we picked a terrible market and optimized the product for the wrong metrics of goodness. Each mistake likely cut RethinkDB’s valuation by one to two orders of magnitude. So if we got either of these right, RethinkDB would have been the size of MongoDB, and if we got both of them right, we eventually could have been the size of Red Hat.
 Don’t read into these numbers too closely. I’m ball-parking it, but it should give you a general idea of the cost of these mistakes.