Here is a good article simplifying SEO Search Engine Optimization (SEO), which you should all know about. SEO is important for your website so people can find you when they do searches by topic. If you have a blog, it is helpful to put keywords into your post titles now and then. Amazon also uses a type of SEO called tags. Be sure to tag your Amazon book listing with keywords, but not keywords that are so popular you get lost in a crowd - be a little specific (this goes for blogs, blogpost titles, and websites, too).
http://blog.nathanbransford.com/2011/12/what-you-need-to-know-about-seo.html