What does Getting Out of the Building mean?

“Steve Blank’s short hand for not accepting your business assumptions as true. Go speak (in person, if possible) with living, breathing customers to determine the validity of your assumptions.”

This is part of an ongoing series of concept definitions from “The Entrepreneur’s Guide 
to Customer Development” by Brant Cooper & Patrick Vlaskovits. This book is an awesome extension of the work Steve Blank started in “Four Steps to the Epiphany.” You can get a copy of the book today at http://custdev.com. I highly recommend it.