As more and more online magazines and newspapers launch Kindle and tablet editions of their content, Amazon search results are becoming almost as critical as Google rankings.If you’re already publishing — or thinking of publishing — your premium content on Kindle devices, you may also want to take advantage of Amazon’s “Kindle Publishing for Blogs” program. In a couple of easy steps, you can sell your free content for a low monthly subscription rate of $0.99 – $1.99/month.As Amazon sets such a low, non-negotiable price, this obviously isn’t a lucrative revenue stream (especially since you only get a small percentage of the monthly subscription rate). However, publishing your free content should increase search result rankings for your brand, especially if you invite customer reviews. And with Amazon’s automated recommendations to readers, you’re sure to sell more of your premium content as well.At the same time, there are many caveats, especially depending on the type of content you produce and your publication’s strategic goals. To learn if publishing your content on Kindle devices is right for you, check out this week’s How-to article on our sister site, Subscription Site Insider. It’s got lots of great tips, as well as screenshots of how three subscription sites — including The New York Times — are using this program in three different ways.