Web 2.0 is Message Passing
When computers get large enough, we give up on shared memory and have parts of a program communicate by passing notes (messages) instead. The most popular way to do this for supercomputers is MPI (Message passing Interface).
Without the heralding of being a new method for parallel programming - the Web 2.0 world has XML, REST, SOAP, JSON - all methods to pass requests, responses and state back and forth between processors.
Has Web 2.0 given us the successors to MPI?
Users of shared memory decry MPI as harder to use and complain that it cannot handle the same degree of fine grained interactions between threads of execution.
I suspect even MPI users would decry any Web 2.0 interface as even worse.
How much is Web 2.0 providing a new parallel programming model?