"As more networks develop, and existing ones grow, the problems of information routing and traffic flow become increasingly more difficult to solve, " says Dr Raine.

BBC: Mapping the flight of the bumblebee

Problems with the order-routing system have caused delays on two other occasions this year.

CNN: Software glitch forces brief shutdown of Nasdaq

While the technique of routing mail via mail servers of net service firms might cause problems for those that use blacklists and block lists it did not mean that other techniques for stopping spam lost their efficacy too.

BBC: PC hard drive, Eyewire