TrustPilot is a community site where people can leave reviews (or, vent) about just about any business or organization.
When looking at AirBnB there, the reviews are really quite bad, and there are a lot of them.
https://www.trustpilot.com/review/www.airbnb.com
I read though many of them, and I think the reason why so many people go on there to vent is the following: Many of the bad reviews are about a cancellation: typically a host cancelling on them which causes them a problem, but also the guest cancelling on the first day when the place is seriously below expectations. Both things just can't be helped, it's the nature of AirBnB and it probably doesn't happen too often. However, in both these cases the guest ends up feeling 'bad', yet there is no opportunity to leave a review of the host or place on AirBnB, even when the guest cancels after seeing the plece and finding it lacking. This I think then causes people to go search out other places online to complain and 'vent' a bit, causing relatively a lot of bad reviews.
So if AirBnB wanted to improve this, they could offer guests who cancel /after/ check in the opportunity to review the place, which would actually be helpful for other guests, or in case the host cancels then in that case too they could be given the opportunity to reflect a bit on how the host handled it in an AirBnB review.
And then secondly if AirBnB wanted to crowd out the bad reviews, they could request guests who just put in a 5 star review of their stay, to now also go online on TrustPilot and say some nice words there. (The AirBnB site is generally quite good at coaching people what to do next.)
(Then again it may just not be too much of a poblem, likely many of you here have never heard of TrustPilot? )