it's a thorny problem. it's going to hinge entirely upon reputation and identity authentication as far as the average user is concerned, that's, unfortunately, how humans manage the division of labor, leadership is our vulnerability.
as for whether it is practical for the big silos to adopt the small, horizontal model at all, that remains to be seen. i'd say it will end up being similar to CDNs et al, with distributed databases enabling massive relays with single DNS names.
this is the sort of detail that will be important in the "verify" thing.