When you design something from the standpoint of benefits, or function, you are much more likely to come up with a solution that performs better, not just something that’s more efficient. 

A friend just forwarded me an article about Aviointeriors' new "stand-up" airplane seat.  The design requires people to lean or stand in a partially reclined position on relatively short flights (up to four hours).  It decreases the amount of horizontal space required per person from 31" to 23".  Airlines would be able to get more people on a plane, save fuel use per passenger, and reduce the number of planes required.  When my friend asked me if this was an example of dMASS, I said, "No!"  But it does provide a good opportunity to explain this central principle: dMass is not the same as efficiency

dMASS is about improving the ratio of value to mass.  More value delivered with less mass.  dMASS can be a means to achieve efficiency, but rarely to optimize it.  It can also be a great way to improve profits, but not necessarily to maximize them.  dMASS is about performance, and performance is about delivering what matters to people who need it.  

How might a designer approach this situation differently and come up with a solution that performs better?  The simplest answer is to design for the whole system.  You might look at the largest system in this case - transportation - and think about better alternatives for transporting people over medium distances.  The least-mass solution is not moving people at all.  Instead, I would focus on enabling people to transfer data and ideas to others, trying to minimize the gap between telecommunications and face-to-face interaction, and making the benefits of face-to-face over virtual interaction negligible compared to the costs.  I regularly work with colleagues in Europe, the Middle East, and North America through Skype and online tools like Central Desktop, something that's occurring on a scale barely imaginable 20 years ago. 

Of course, there are other reasons we travel.  When we do, we benefit from better design.  dMASS thinking requires considering multiple criteria.  A plane should be fast, safe, fuel efficient, and at least reasonably comfortable.  Engineers need to look at the whole and design for all of these factors.  We tend to falter when we take one piece out of something and focus on one criterion.  In this case, it was looking at just seats and space.  The seat design also just seemed to consider one customer - the airline buying seats.  But there's another customer - the person buying a ticket to sit in a seat.  People will put up with a lot of discomfort in order to get to their destination a little more cheaply, but we all have our limits. 

If you're designing a component that's part of a larger system, you still have to consider multiple criteria.  An airline seat that's more like the new Herman Miller chair could be more comfortable, safer, waste less room for padding, and weigh much less, saving fuel. 

When we ask "How can we make something more efficient?" I think the tendency is to get stuck in a box, tweaking the existing design and sometimes making it worse.  Instead, we should be asking "How can we deliver the same or better benefits using fewer resources?"  When you think of something from the standpoint of benefits, or function, you are much more likely to come up with a solution that performs better, not just something that's more efficient.