There is another option, which is having users donate money, hardware and
bandwidth. That is what Wikipedia is doing. The Bomis people are nowhere
rich enough to fund Wikipedia on their own. Companies such as Yahoo and
Answers.com are contributing funds and/or servers and bandwidth.
http://meta.wikimedia.org/wiki/Wikimedia_servers/hardware_orders
http://wikimediafoundation.org/wiki/Budget/2005
Lots of other projects get along well this way, too. I think we can safely
say that most open source projects have some kind of corporate
sponsorship, either through using services at sourceforge or some other
OSS services site, or directly by donations. Some sites, like sunsite, I
think, are government sponsored as well.
More could probably be done to obtain government sponsorship of socially
valuable projects like sourceforge to avoid relying on the whim of
corporations.