Authors den is a free comprehensive online writing community which prides themselves in having the largest amount of users, with over 1.4 million readers a month. Authors are able to post their original writings and gain feedback from the vast number of readers on the site.

You are also able to sell your book on this site, allowing other users to purchase straight from your profile page. Membership is free, but they also offer an advanced author marketing memberships (in four different levels) although not many extra features are gained through a paid membership. Authors can track their page traffic and also optimize their results in search engines such as Google. This site is great for the authors who are ready to sell and distribute their books. With an excellent amount of users, this is an excellent way to gain sales and create an audience for your book.
 
URL: http://www.authorsden.com/