What is a sustainable startup?

Block and Tackle Businesses. That's what my father-in-law calls them, regular businesses that aren't going for sexy venture funding, but critical to a functioning economy. Businesses that perform a valuable function, and grow on their own revenue more than anything else.
A business is sustainable when it has a positive impact on the world. A sustainable business is one that not only generates profit, but does so without overly exploiting the resources around it, and improves the world in some way while doing it.
We all consume resources. Air. Meat. Oil. Water. We're taking things out of our environment every day, and using it to survive. Hopefully, we do something meaningful for somebody, and leave the world a better place. At least when we're done, we're food for worms, to quote the Dead Poets Society. Fertilizer for future generations.
As we've come to inhabit most of the habitable parts of our planet, and many of the inhabitable parts, we've done a lot to destroy the habitat that keeps us alive. I'm not all that concerned about the earth itself -- it's going to go on long after we're gone. But I do happen to care about us humans who live on it, and I'd like to see us continue for more than the next couple centuries.
So big picture, that means doing things to strengthen the natural systems that sustain us, rather than exploit as much of them as possible for short term gain. That means building businesses that are concerned about the costs to the next 7 generations, not just the next 7 weeks.
So what does this have to do with building web sites?
I have this crazy conviction that our current economy based on enormous out-of-control corporations are doing far more to destroy our future than nearly anything else we do. They are not too big to fail -- they are too big to survive. They have, by law, one overriding purpose -- to make money for their shareholders. Everything else is secondary. And when that profit is taken from shared resources, without any accurate accounting for the long term costs of that exploitation, well, that's not sustainable. Sooner or later the resources run out, and the company goes over a cliff. Potentially dragging the rest of us along, too.
And I also have a crazy belief that I can do something about it, in some small way. I can take the ideas of a bunch of other developers, improve them, and give them back. I can apply these ideas to a myriad of challenges that other sustainable businesses face, and help them compete with the out-of-control companies. We can create an economy of responsible, sustainable businesses that are about people, place, and profit. Small pieces loosely joined is the Unix architecture, and it's extremely resilient to attacks, failures, and change. The Internet has inherited that architecture, and has proven itself capable of bringing down dictators. I believe that working together, we can create more jobs, restore our ecological systems, and weather more storms -- even economic storms caused by out-of-control corporations and Wall Street greed.
Or maybe I'm just crazy.