The program energy efficiency optimist's view
Despite what I wrote last entry, I think that there is an energy efficiency optimist's view and that it has a lot of validity. It goes like this:
First, there are an increasing number of interesting devices on which power efficiency really does matter significantly, either because it saves you money (such as compute clouds where you are charged very precisely for resource usage) or because it lets you run at all (laptops on battery power, low-power netbooks, cellphones, and so on).
Second, there is likely a collection of various easy energy efficiency improvements that haven't been made, either because the programmers involved haven't looked for them before now or because they haven't cared; before there were interesting devices where this really mattered, being energy inefficient probably just made your program run slowly (if you even noticed).
Thus the optimist's view is that the problem matters and we have ways to make relatively rapid, meaningful progress. In the process we may even improve things for other people, making real differences in things like startup times.
(This is the same view as the optimist for anything, broadly that the new problem matters and we can easily do things about it now that we actually care.)
(This seems to be actually working in the Linux world, at least to some degree, and creating useful results. Although I can't dig up the references right now, I have a memory that people looking into these issues turned up the fact that some programs looked at several thousand files on startup, which had obvious bad effects on the startup time even on fast desktop machines.)