This talk/interview of Keith Rabois is great when it comes to talking about what a COO does: http://firstround.com/article/Keith-Rabois-on-the-role-of-a-COO-how

This talk/interview of Keith Rabois is great when it comes to talking about what a COO does: http://firstround.com/article/Keith-Rabois-on-the-role-of-a-COO-how-to-hire-and-why-transparency-matters http://firstround.com/article/Keith-Rabois-on-the-role-of-a-...