If you haven't been following the brouhaha around Wikipedia recently, Glyn Moody's excellent synopsis will give you the skinny. It turns out that Wikipedia is more open than anyone thought, not only because anyone can theoretically edit it, but also because it records the IP addresses of those who do.
My favorite? Microsoft's view of itself:
Microsoft's MSN Search is now "a major competitor to Google." Take it from this anonymous contributor, whose IP address belongs to Waggener Edstrom, Microsoft's PR firm.
Naughty, naughty. But not unexpected. In fact, it's this very tendency of humans to be human that makes Wikipedia's architecture of transparency, of openness, so critical. Tim O'Reilly likes to talk about the architecture of participation, and he's right to do so. It is important.
But I think an architecture of transparency is even more vital to the health of online and open-source communities because it guarantees the possibility of trust within communities. In open source, this translates into open-source licenses that guarantee access to source code, which guarantees that everything else (community, governance, etc.) is possible and fruitful.
The next time someone tells you that source code doesn't matter, point to Wikipedia. Access to the source (in this case, the contributors) is critical to making Wikipedia function, just as access to source code is critical in an open-source project. It would be nice to have IP addresses tracked in open source, as well, though we accomplish the same thing in other ways.
All of which breeds trust, which breeds great code.