I work there, just saw this.
Bluebox was an old project to provide a GUI for freeswitch. Kazoo has been the focus for the past 4 years, bluebox is now a community project if I recall correctly.
Kazoo is a multi-tenant hosted pbx and trunking solution. It is an erlang cluster which uses amqp as a messaging bus and erlang apps which provide centralized call control and features across multiple freeswitch (media server) and kamailio servers (sip proxy). A shared cluster wide database is provided by bigcouch.
The difference between this and a cluster of asterisks (or broadcloud, kandy etc) is that you as a user or account, are not tied to a single server, any phone on your cluster can utilize the resources of the entire cluster as the erlang apps and AMQP bus provide a glue joining all servers in the cluster into a single "switch". Most of the "cloud" telephony out there is not distributed, it is mostly a lot of boxes with at best HA fail-over to another box that sits in as a warm standby with a unified provisioning layer to hide this from the users.
You can checkout kazoo at github http://github.com/2600hz/kazoo
There is a kazoo all in one ISO, which lets you run all the services in a cluster via a single server. You can get it at http://repo.2600hz.com/ISOs version 2 has the new GUI monster-UI.
Edit: phone does not a good comment make, spelling broken links ...