One of my favorite bloggers Jason Kottke at
kottke.org has quit his day job to pursue blogging as a fulltime gig. I support his effort, but I think his method of generating capital by forgoing advertising and instead asking for donations will not be overly successful. The idea of asking people to pay for a blog will generate some revenue, but it will not generate enough to survive on.
He will benefit from the initial exposure that his announcement has received, but after that I think he will have exhausted most of the people who would pay to support him. Blog traffic (especially to a site like his) tends to breakdown between the loyal readers who frequently visit his site and the new people who discover his site by clicking on some link. The loyal readers are the ones who will provide the bulk of the donations, and while I am sure they are numerous, I doubt they are enough.