I was just re-reading Kathleen Gilroy's excerpt of John Udell's column, The Network is the Blog and thinking about it in terms of the scale-free networks described in Linked, which I just finished reading.
In his chapter “Achilles' Heel” Barabási describes the interplay
between robustness and vulnerability. What does robustness under
failure and vulnerability under attack mean for a blog network? It
means that the hubs are extremely important, especially when there are
very few of them. If we are cultivating a blog network, we need to be
especially encouraging and protective of the hubs.