You can give away content in the form of actual books on blogs, or digitally in chapters on any and all Web sites. (writerswin.com)
Some of this divergence can be explained by the fact that parents want to read actual books with colorful pictures to their children. (media.thinknum.com)
Some authors have used FB ads to increase their mailing lists, but for actual book sales, I haven't seen anyone who can analyze this. (killzoneblog.com)