What a $20 billion startup looks like when it's just starting out, and everyone thinks the idea is stupid: Here's Airbnb's first-ever pitch deck

Airbnb is a great startup success story. It's reportedly raising a new round of financing that will value the company around $20 billion.

But when Airbnb was first getting started in 2008, the founders struggled and would-be investors snubbed their idea.

The founders shared their first pitch deck with an MBA student, back when it wanted to be an air mattress rental company.