The Economist writes about the work done by Barabasi (author of “Linked”):
Scale-free topology is resistant to random failuresone reason the Internet, despite the lack of artifice in its design, has proved so reliable. On the other hand, because there are disproportionately many hubs (as well-connected routers are known), the net is particularly susceptible to deliberate attacks on those hubs, the sort of thing that cyberterrorists might attempt.
Already, understanding the net’s scale-free structure has led to new results. For example, it had long been thought that the best way to curb the spread of a computer virus was to change the software of machines on the net so that they were less easily infected. Studies using random graphs had shown that changing the software on more and more machines had a cumulative effect. That is not true in a scale-free setting. There, most software changes make no difference to the rate at which a virus spreads (although they obviously protect the machines in question). However, treating a relatively small number of hubs in a scale-free system can stamp viruses out completely.