I do not know how Taz operates, but a trust owns the Guardian, so it is somewhat immune from the demands of capitalist ownership. And it seems that the Scott Trust itself would not exist, but for the estate tax.
<http://www.guardian.co.uk/information/theguardian/story/0,,1038110,00.html> "CP Scott died in 1932 and was followed only four months later by Edward, so sole ownership fell to JR Scott. Faced with the potential of crippling death duties and the predatory interest of competitors, Scott contemplated a radical move to ensure the future of both the Guardian and the highly profitable Manchester Evening News. He concluded that the only solution was to give away his inheritance, a far-reaching solution which provoked close advisor (and future Lord Chancellor) Gavin Simonds to conclude: 'you are trying to do something which is very repugnant to the law of England. You are trying to divest yourself of a property right'."
The closest American comparison that I can think of in terms of ownership structure (but certainly not longtime political outlook) is the St. Petersburg Times, which is owned by the Poynter Institute for Media Studies.
--tim francis-wright