[adrusi]

Yes but that doesn't require a central host. If your friend is connected to the network you can join it via them.

[voltagex_]

If I've just downloaded SomeCoolNewTool that's using the network, are there bootstrap hosts pre-loaded? Who's my "friend" in that case? Are there trust issues here?

[cf]

In practice, SomeCoolNewTool will be bundled with some seed hosts.