LangCleg: "No, it also asks people to front up monthly."
Well, yes, that's what I meant by "make regular donations".
The point is, to read the Guardian online you don't have to subscribe, whereas to read the Times you do.
The Guardian's misfortunes are its own doing. It has seen print sales plummet in the last 10 years, but then so have all the newspapers (the Times's print sales have held up better than most, but they're still have of what they were 10 years ago). The Guardian's previous editor, Alan Rusbridger, came up, Baldrick-style, with a cunning plan. If he put all the print content online for free, along with additional web-only content, he could attract a huge worldwide audience and, with it, massive online advertising.
The first part of the plan succeeded. The Guardian is the second most-read news site in the world (the first is Mail Online). But the second part failed big time. Instead of flocking to the Guardian, brands chose instead to advertise on Google and Facebook which, between them, now attract about 80% of online advertising.
The Guardian is now stuck. People don't buy the print edition because all the content, and more, is available on the website. It can't really ask for subs because much of its audience is in the US and Australia and the payment mechanisms would be too complicated. So it has resorted to asking people to make monthly donations for small rewards, such as tickets to events where Guardian journalists talk about journalism. They have actually done quite well with this model - from making a huge multimillion pound loss a couple of years ago, they are now close to breaking even. But whether that is a sustainable model is open to question.