Scribd, the popular site for sharing documents, has launched a store that could eventually grow into a serious competitor to Amazon. There’s a bit of David-and-Goliath to the battle (not that Scribd has to kill Amazon to succeed), but there are reasons to think the smaller site might become a major player: Not only does it already attract 60 million readers a month for its free content, but its accessibility and flexibility could make it a good fit for authors who don’t want to go through a traditional publisher.

The most prominent example in Scribd’s beta test is Tamim Ansary, author of West of Kabul, East of New York. Ansary is a New York Times-bestselling author, but Tammy Nam, Scribd’s vice president of content and marketing, says that since his success has been in nonfiction, Ansary’s publisher didn’t want to back his novel. (By the way, I find that anecdote incredibly depressing.) Instead, Ansary is putting the book up on Scribd. And since the company gives 80 percent of the revenue to the seller, he could make a lot more money this way, even if he sells fewer copies overall. Another big launch partner is O’Reilly Media, which is publishing The Twitter Book by Tim O’Reilly and Sarah Milstein on Scribd before releasing the print edition.

Another promising thing about Scribd is the way it lets sellers experiment with different pricing models — you can sell your writing for as much or as little as you think it’s worth, or sell individual chunks for a lower price (a model that makes sense for travel books and technical books, for example). Plus, you can change the price whenever you want, making experimentation easy. Nam says an iPhone application is coming next month and that Scribd is considering other models, such as allowing users to view a document for free, then charging if they want to download it.

The Scribd Store announcement comes right after the launch of competitor DocStoc’s DocCash program, which is also focused on making money from documents, albeit through ads rather than charging. Scribd has raised more than $12 million in venture funding.

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