Does publishing your book on the Web help sales?

Many authors have touted the effects of publishing your book on the Web as a promotional tool for bookstore sales.
This New York Times article Crossover Dreams: Turning Free Web Work Into Real Book Sales reports regarding the Diary of a Wimpy Kid, which was published free online: “Mr. Kinney, a design director at Family Education Network, a unit of Pearson that operates Funbrain, where ‘Wimpy Kid’ first appeared, spent 10 years writing the book and always intended to publish it in print form. But after discussing it with his boss, Jess Brallier, the publisher of the Family Education Network, Mr. Kinney decided to serialize his book on Funbrain.com in part to attract children to the site during the summer. As an unknown author, he figured he might gain more exposure if he published the book — which looks as if it could be a hand-written diary of a mischievous middle-school boy — on a Web site with thousands of daily visitors in his target market.”
However, PublishersLunch Deluxe, from PublishersMarketplace says:
The NYT cites the illustrated children’s novel DIARY OF A WIMPY KID as the latest example that material available for free on the internet can still have value in traditional book form. In this case, Abrams has sold 147,000 copies tracked via Bookscan, and a larger version of what became the book (1,300 online pages in all) remains posted at Funbrain.com, where it has been a popular feature. But at least one retailer says the sales are due to good word-of-mouth for the book rather than viral attention driven by the web version.
So what’s best? Should you publish your book online free as a promotional tool as you write the book?
My gut feeling, if you’re a new writer, and don’t know much about selling your book is – yes.
You get these benefits:
* a readership
* publisher interest once the readership is big enough
* confidence in yourself – readers tend to give you confidence
* motivation to continue writing, because of the interaction with readers.
Angela Booth
Info Product Maestro: Make $500 a Day with Your Information Products