Interesting conversation with Tim O'Reilly on Port 25  :

"as we build these new applications ... it's less and less about source and more and more about shared activity ... we're moving into the era of network effects in data ... and increasing returns that come from collaboration ... and systems that get better as more people use them ... look if you gave Richard Stallman every bit of Google source code he couldn't make Google ... this is a transitional stage ... there are principles in the open source definition that are good principles but we have to transform them and ask ourselves what does that mean (GPL to enforce reciprocity of web services?) ..."

http://port25.technet.com/archive/2006/07/27/OSCON-Interview-_2300_1_3A00_--Tim-O_2700_Reilly.aspx