roddie

They can (and did) scale their e-commerce "servers" (actually services) for the launch, because those kinds of applications scale easily. Email servers, however, do not necessarily scale easily and that's where the bottleneck was, which cascades to the website because that's what is trying to talk to the email server(s). I imagine it wasn't unexpected, since they had the same (plus a couple of other) bottlenecks last time.