This is an interesting forward looking paper which I would recommend
for publication after significant revision.
The economic model for computing resources is important and already
has had major impact on computer technology. For instance the trend to
using distributed computers (departmental machines) is partly due to
economic forces. Centralized Systems are difficult to manage
efficiently as if you charge then the machine is underutilized while
if any time is given away then it is saturated -- such tradeoffs
(and avoiding the tragedy of the commons with free time) is much easier
in small peer communities (such as departments)
I see the difference between time and cost optimized scheduling as
important and needing further research

That said, I found the paper disappointing. There was little discussion
of P2P concepts (trust, digital cash, reputation) but rather a
slightly superficial (IMHO) discussion of analogies with the real
world in section 3. Further I didn't really see much in sections 5 and
6 describing the technology and policy behind Grid economy based scheduling.
Note "trust" and "reputation" are critical -- they are basis of peer review
used in time allocation on most large computers.
Section 6 needs expansion -- one experiment is insufficient to make a point