高分求助1篇英文文献，最好带翻译，要与SEO相关

Search engine optimization
　　Search engine optimization is essentially the science of designing your web site to maximize your
　　search engine rankings. This means that all of the elements of your web site are created with the
　　goal of obtaining high search engine rankings. Those elements include:
　　Entry and exit pages
　　Page titles
　　Site content
　　Graphics
　　Web site structure

　　In addition to these elements, however, you also have to consider things like keywords, links, HTML,
　　and meta-tagging. Even after you have all the elements of your page optimized for search-engine
　　friendliness, there are other things to consider. For example, you can have all the right design elements
　　included in your web pages and still have a relatively low search engine ranking. Factors such
　　as advertising campaigns and update frequencies also affect your SEO efforts.
　　All of this means that you should understand that