Copyblogger used Amazon Kindle Direct Publishing to increase its audience by more than 24,000 readers in just 3 days.

They wrote up a blog post on Amazon content marketing:

1. Sign up. Sign up for the Amazon KDP program so you can self-publish.

2. Prepare. Format your eBook with a tool like Scrivener and then upload it from the "Enroll in KDP Select Program", which allows you to give away your book for any five days over a 90 day period.

3. Promote. Plan the event "Free eBook" at least 48 hours in advance, and use your existing audience as evangelists.

4. Remind people again before it expires. The essence of good marketing.

Results: His eBook was downloaded 24k times, and his email list grew. Once you break the Top 100 on Amazon, this can earn you a lot of attention on book forums, blogs, and other websites. Plus, it’s great social proof for future sales (“An Amazon Best Seller!”).

The week after the promo, he sold 50% more books than the one before. Sales now average 1000/month (that’s about $3500 in net profit off of a book: not too shabby!) ...

James Altucher says books are the new business card.

He calls the new self publishing movement Publishing 3.0.

He describes his success self publishing a best seller, and explains how you can do it too:

http://techcrunch.com/2013/07/20/how-to-self-publish-a-bestseller-publishing-3-0/