On problem with that scheme: I never, ever talk to my closest friend on Facebook. In fact, if we were able to get an objective measure of closeness/intimacy for each of my friends, created and ordered list from that measure, facebook contact frequency would peak well below the top of the list because other communication modes would take over: email, instant messaging, text messaging, phone calls, hard drinking in bars, etc.

For any algorithm to do better than a rough approximation, it would have to be aware of all communication modes to some extent.

(Unless, of course, there are people who only interact on facebook.)

Consumers do not consider (quantify) the energy cost of operating some gadget over its lifetime so it is the upfront (manufacturing) price that attracts consumer dollars. And it is cheaper to build a less efficient device than a more efficient one.

Maybe I am getting old, but I'm always surprised when someone brings up Zelda in a design discussion and doesn't talk about a Link to the Past.