From where I work, Storage Efficiency is also about how the users and administrators interact with the storage system. Making it efficient is not just about being able to make the most of the physical blocks on the disk, it's about being able to easily provision flexible storage, and how the end user can interact with this seamlessly.
For an Administrator, we provide the tools to make this easy for each department. The Exchange administrator has a familiar interface that they already recognise from administering Exchange, so the storage element feels native to them. Provisioning, growing and protecting this storage is simple and easy for them. Products like the much awaited Systems Manager make these even more flexible and transparent for these administrators. An MMC interface they are used to using available at their fingertips!
For the Unix teams, we give a very similar interface, the command line has close parity with a lot of commonly used commands and the syntax is easy to follow and easy to pickup. It's also easily scriptable which makes it a very powerful appliance. This ticks all the right boxes for the Unix teams and gives them efficient use of the storage appliance. They hit the ground running and they don't need to re-learn a new system to start working.
All administrators have the ability to control their own storage (including BURA and BC/DR), this makes the process and workflow of the entire enterprise more efficient. No need for any lengthy retraining or waiting for people to understand an entirely new system. The storage just slots into the workflow and people get new useful features that slot into their existing way of running, not another system to manage and another headache to deal with.
For the end user, one of my favourite features is the VSS client integration. Having the most powerful and efficient snapshot technology around is fantastic stuff, but being able to get the end user the ability to restore anything they need in 2 clicks is priceless when it comes to efficiency. The end user themselves is now self sufficient! Each SMAI product has ways of giving the end-users easy ways to interact with the storage system.
So for me, although Storage Efficiency is great at the block level, this is only half the story. Making storage efficiency work at the human level is priceless, and for me this is where NetApp solutions fit so well.