Interestingly enough, there's now an Austin-area group that focuses on exactly this theory: Volunteer technology work to bootstrap both startups' products and

Interestingly enough, there's now an Austin-area group that focuses on exactly this theory: Volunteer technology work to bootstrap both startups' products and individuals' careers. You work for free as a way of building social capital. I'm doing it right now, working on a startup's webapp for $0/hr with the understanding that if the founder likes my commits at the end of the week I will be hired as a contractor for $N/hr.