From Teaching Computers to Work in Unison:
"The grid is widely regarded as the next stage for the Internet after the World Wide Web. The Web is the Internet's multimedia retrieval system, providing access to text, images, music and video. The promise of the grid is to add a problem-solving system."
...
"Our belief was that open source was the best way to maximize adoption," he said. "Globus is an infrastructure technology, and it is only going to be successful if everyone uses it. And if you're doing something that is primarily funded by the government, sharing the software seemed the most appropriate thing to do."
Apparently, the difference between grid computing and distributed computing is in the ability to provide for 'collective' problem solving.
