Looks very cute, and might be useful (not having to leave the terminal is always good), but I think I speak for many others saying that I don't want to start a new address book from scratch, let alone one that won't sync into my other devices.

So my suggestion for the killer feature here is an ability to sync with some major service provider such as iCloud or Google (preferably both / some standard protocol?). I'd love to help the development of such a feature.