The functionality to handle this is mentioned in the blog post: "standby" peer mode.
"Our upcoming release, etcd 0.4, adds a new feature, standby mode. It is an important first step in allowing etcd clusters to grow beyond just the peers that participate in consensus."
Fair enough, it just sounded like the GP was describing something inherent rather than something new, and it didn't mesh with my understanding of how etcd worked to date.
