What are the top ten most influential parallel and distributed processing concepts of the past millenium?

This is a report on a panel titled "What are the top ten most influential parallel and distributed processing concepts of the last millenium?" that was held at the IEEE Computer Society sponsored "14th International Parallel and Distributed Processing Symposium (IPDPS 2000)." The panelists were chosen to represent a variety of perspectives and technical areas. After the panelists had presented their choices for the top ten, an open discussion was held among the audience and panelists. At the end of the discussion, a ballot was distributed for the audience to vote on the top ten concepts (in arbitrary order). The voting identified the following ten most influential parallel and distributed processing concepts of the last millenium: (1) Amdahl's law and scalability, (2) Arpanet and Internet, (3) pipelining, (4) divide and conquer approach, (5) multiprogramming, (6) synchronization (including semaphores), (7) load balancing, (8) message passing and packet switching, (9) cluster computing, and (10) multithreaded (lightweight) program execution.