It should have happened the other way around.
First there should have been a significant increase in social capital.
We should have seen most trust developing between people.
Then all these new tools should have come along to take advantage of that trust
Instead, as Wired magazine notes below, technology is creating the trust.
"We are hopping into strangers’ cars (Lyft, Sidecar, Uber), welcoming them into our spare rooms (Airbnb), dropping our dogs off at their houses (DogVacay, Rover), and eating food in their dining rooms (Feastly). We are letting them rent our cars (RelayRides, Getaround), our boats (Boatbound), our houses (HomeAway), and our power tools (Zilok)"
You don't need members to know, like, or trust each other when you begin (it helps if they do. mind). You just need to find that initial spark and keep it going.
Community building isn't creating the technology, it's building these relationships. People build trust through experience and technology makes that experience possible. The technology makes it easier, but it's you that makes it happen.
(Aside, the crazy thing about building a community is you don't know what sort of behaviors you're going to create and new rules you must introduce.)