Wired News has afrom (which doesn’t seem to have any content on it today for some reason) which has some good basic information on making a living from blogging.
Interestingly he puts a dollar value on a per page basis(over a year) to blogging:
‘As for money, people who are really in the business of making a living off content pages say they average about $10 a page per year. That would be a pretty good average. Usually, it’s not enough to make a living on, but it’s a good supplement.’
I’d actually not considered measuring income in terms of a per page basis. I’m not sure it’s a terribly good measure because it would vary so much depending upon the level of traffic that you get to your page per year and the topic of the page (and the resulting click value in AdSense) but it’s an interesting one to calculate.
Here at ProBlogger I’d say that my figures are well and truly under the $10 per year per post figure (they are probably a third of it) but on some of my other blogs they are much higher. In fact overall my blogs I’d say it’d be a conservative estimate.