How is something no one has ever heard of worth $3.9b?
Also worth pointing out that HomeAway only offers whole home rentals, they do not offer room-only (like Airbnb) so is not 100% part of the same 'sharing economy'.
What did I do? I found a place on AirBnB and was able to book it no problem. So I have a hard time seeing how the HomeAway / VRBO experience could come even close.