The Australian operation of the Guardian has said recently that donations from readers are now more than 50% of the revenue. And they’re trying to increase that percentage further. Not sure about their UK or US operations.
That is quite phenomenal really - I don't think any other widely-used service (other than actual charities) operates on that basis. Though I don't really see my monthly payment (a whole $10, mind you) as a donation. But their spiel that convinces readers to do so is well-written, and hooked me in. Well that, and just a look at how bad the quality of most other online news sources was, seemingly particularly the ones operated by profitable companies.