I guess I just don’t get how being open sourced code is really relevant to Wikipedia? The code is not special is it? They don’t need donations to pay for elite programmers, it’s servers and IT people. The code being open source means that someone else can copy their own Wikipedia if they felt like competing and thought for some reason that they could. The fact that Wikipedia Foundation is non-profit basically precludes this but I think you answered my question basically anyway, they don’t rely on only donations.

It's relevant that it's open source because you don't have to pay for it and a competitor could arise (iirc there is a startup that does that, provide a "better" user interface to wikipedia), and the software is pretty complex so you should pay full time programmers and UX researchers and designers.

The Wikipedia software is used by many institutions. When i still worked in uni, we tried it for our group internal documenting. In the end went for a less complex wiki software, though. :-)