And too many Kindle books...
I haven't ever paid for any blog-type content, but I probably would if someone marketed it right.
With advertising, I don't see why everyone's assuming it would be impossible on a plain text medium.
I listen to podcasts that have sponsors. They just talk about their sponsors in the middle of the show. They try to make it sincere ("I use this product myself" etc). It seems to me like this is a very high quality type of advertising, compared to blockable little ad server banners.