FB success was based on tricking their users into giving FB access to their email accounts and spamming all their contacts. I assume this is no good way for an alternative network to find users.

It is great when Diaspora becomes a network of more conscious people that use their brain before giving access to their private data + contacts to some company - one of the best "selling points" is quality, in the long run, not quantity.

FB will be a "dumb-teeny-place" in a few years, decentralized and privacy-protecting networks will win, but grow much slower. No problem with that.