I'm sure the comparison has already been made on another thread, but Airbnb looks to be very similar to Couchsurfing in certain important ways. If the question is "how can Airbnb (re)build trust?", a valid answer would be "in a similar way to how Couchsurfing has."
Although perhaps I'm missing some critical difference between the two.
Is there a particular project you have in mind here, or is it just a general statement?