What to Post
It is most common for beginning fiction writers to post their first draft or second draft onto their blog. They do this by posting one chapter a day or one chapter a week. Like a serial book published in a magazine, the writer builds a fan base and builds tension and suspense by not posting all of the book at once.
After the Book has been Posted
After the entire book has been posted to the blog, it continues to go through a series of edits. Sometimes readers are good enough to critique the work and post comments about strong and weak spots in the book. Any good writer will take the good and the bad into consideration as she or he continues with the book edits.
There was a time when publishers would not touch a manuscript that was first published online. With the introduction of self publishing on Kindle and other ebook platforms, the loss is on the side of the publishers.
Writers are now able to take their final, edited draft and publish it themselves. They have worked to build up their fan base, they built a list of potential buyers of the book they have posted online and, many times, readers will go on to read the finished version of the book as well as purchase any other books published by the writer.