FreeBSD has corporate sponsors. In addition to the many companies who hire FreeBSD developers and let them loose to hack code and the companies which provide lots of hardware and hosting infrastructure (Juniper, Yahoo, NYI), the FreeBSD Foundation has been receiving large donations every year from NetApp and Hudson River Trading, as well as smaller annual donations from iXsystems, Google, McAfee, and SwissCom. And then there was the anonymous $100k donation last year... I don't know where that came from (obviously) but I'm guessing it was a large corporate FreeBSD user.