Couldn't they harness this?
I mean imagine having a million-node Tor network. You could hide the source of your packets in /your own private onion routing system/. Even just having that many end-points would make the system so much more secure that you'd be able to charge crims/spooks for using it.
Which is probably what'll start happening shortly- criminals using billion-node TOR-like strategies to hide their communications. And the NSA will, once again, be more or less powerless.- monitoring 4,000 nodes is realtively simple, but monitoring 1,000,000 constantly changing (as users cleanse their systems and others get infected) nodes would be a considerable increase in difficulty.
Remembering that each computer on the node connects to other nodes unknowingly but also carrys legitimate traffic, let's say a node links to 100 other computers a day in both knowing and criminal-TOR-ed traffic. That's a number picked out of the air and would suggest a LOT of traffic or a very low-packet-density routing system. That means the NSA would have to track >100,000,000 nodes rather than the 400,000 nodes that would have to be tracked with the current 4000-node system. You're talking an increase in complexity of 3 orders of magnitude for anyone wanting to build a map of the system for the purposes of monitoring it, and assuming the same traffic you'd have 3 orders of magnitude less traffic per node to work with.
Unfortunately this just means that taxes will go up in the US to fund a trillion-dollar mega-giga-exaFLOP supercomputer for the spooks...