Entanglement
There is an interesting podcast on Science Talk titled The Coming Entanglement, with Fred Guterl interviewing Bill Joy, co-founder of Sun Microsystems, and Danny Hillis.
The basic argument by Joy and Hillis is that we are reaching a point where our systems are so entangled (most of the conversation is in terms of technical systems) that no one understands the whole thing. They suggest that we need to get over the fact that there is no expert who understands what is going on.
One example is the Windows Operating System, with no-one understanding the entire code. That contrasts to their earlier days when they could hold an entire operating system code in their heads. Another example they gave was that no one knows what would happen if GPS got turned off.
The consequence of this is that when something goes wrong, we no longer have the ability to step back and determine what went wrong. Each system so dependent on the other that you might not be able to restart one system without the other, so cannot restore two mutually dependent systems.
Unlike Y2K, which they (not sure which of the two said this) were optimistic about, the entanglement has moved far beyond the level of complication that existed at that time.
This sounds somewhat like the concept of normal accidents, whereby complex systems will fail. The solution does not lie in preventing accidents, but in decoupling from that system so that the collateral damage is minimised when it surely fails.