[jriddycuz]

Startup companies can come in all forms, but the phrase "startup company" is often associated with high growth, technology oriented companies. -- http://en.wikipedia.org/wiki/Startup_company

This seems to be a reasonably good description of what the word means and what it is commonly associated with. You can call practically any young firm a startup, but it does most commonly refer to PG's definition. Like DHH said in the post, "starting a business" just does not have the near-mythical connotations "startup" has, but those connotations are result of the stories that typical startup culture provides. I don't think there's a way to make "starting a sustainable business" sound sexy because it's not a very sexy idea. And perhaps people with a spouse and kids shouldn't worry too much about how sexy an idea is, but rather how valuable it is.