"Why pay through the nose for something when you can rent it more cheaply from a stranger online? That is the principle behind a range of online services that enable people to share cars, accommodation, bicycles, household appliances and other items..."
“We couldn’t have existed ten years ago, before Facebook, because people weren’t really into sharing,” says Nate Blecharczyk, one of Airbnb’s founders. Airbnb doesn’t require its users to connect their accounts to Facebook, but when people find they have friends in common with another user it sets their minds at ease. Thanks to social media, says David Lee, founder and managing partner of SV Angels, an early investor in Airbnb, “people are generally more comfortable meeting new people using technology.” Providing a secure platform for financial transactions is vital, he says, but creating a trusting community is just as important when it comes to attracting users.
http://ariresearch.org/education-principles/unification-is-always-beneficial