The Bonsai Framework concept of Cloud Density is the philosophy of reducing Cloud cost using a combination of isolation technology ie container technology like and techniques like using zero footprint and multiple instances.
Some examples of enabling isolation technology are Container (FreeBSD Jails, LXC, Docker, Garden) and /or techniques like 0F (Zero Footprint) to capitalize on resources and reduce the number of Cloud virtual machines.platforms (Cloud Foundry, Apache Mesos).
In best practice, the output of Cloud Density should reduced cost due to less Cloud virtual machines. At the same time, the system should match the service level of a standard larger cloud.