I thought I'd start my quest to earn online by Googling the above phrase. The results were mixed to say the least. There was a lot of consensus that healthcare is recession-proof - but you can't do healthcare online on a self-employed basis, especially if you have no healthcare background. The same goes for advice to work for the utilities, police force, military and so on. None can be pursued online.
One potential area that caught my eye was "debt management". Now there is an area where people would probably want free sound debt advice online. I guess the website could be paid for by advertising.
Another area that caught my eye was "comforts". People wanting to cheer themselves up with small comforts such as a bar of chocolate or a glass of wine. Cosmetics such as lipsticks also do well in recessions as women cheer themselves up with small purchases to make themselves look good. This could lend itself to affiliate marketing.
A third potential area to explore is "discount retailing" - the idea is that people become demons about seeking out discounts in recessions, and those who can provide them do the best. I'm not quite sure how a self-employed person with no money and free blogs is going to be able to get into that business though.
The next step will be working out how to exploit these areas online.