In his case, it was a combination of frugality, a decent paying job, and good investing, esp. in real estate (note the "Eventually both rentals were sold and the gains were put elsewhere.") in the "Brief History of the Stash" article. Having gains on real estate probably means he sold them pre-crash.

I'm a fan of the MMM blog because it describes an attainable alternative lifestyle for talented people who aren't already wealthy. It may not be a lifestyle that many people want, but at least it's a change from the high college debt, two income trap, expensive city lifestyle that seems to be the norm for lots of young families.

I don't aspire to live on 20K per year, but thinking about how lowering your personal "burn rate" can give you more freedom in your life is a great mental exercise.