Why purposely including specific keywords in articles, blogs etc. for SEO?

[Jose]

It is all to do with who you want to read the article. You will have to use the keywords you think someone willing to read your article or post will type in the search engines, using the right keywords you will bring only readers interested in your post. There are plenty of resources online where you can find information about this and optimise your posts, http://www.seomoz.org/. Articles in pages with high authority will already rank for relevant keywords, but if you want to start building some authority for your page you will have to optimise your page in order to tell the search engines what your website and articles are about. Remember that search engines dont read articles the same way you do( They cant read images or media, so defining your keywords will give them extra information to index your posts.