He can fix a leaky pipe for one member of a network and use the credits he earned for that job at any other.

CNN: Making no-cash deals with neighbors

It was only a few months ago that DARPA initiated their ambitious Robotics Challenge that reserves a cash prize for a (probably) humanoid robot that can drive to a disaster area and perform several rescue functions including breaking through rubble and closing off a leaky pipe.

FORBES: DARPA's New Challenge: Increase Robotic Power Efficiency By 2,000 Percent