SEO is, in reality, a large part of SMO. A website that has been optimized using SMO principles will contain extensive SEO content. Search engine optimized content incorporates specific, highly searched words and phrases. These "keywords" appear in written content with finely-tuned regularity designed to increase page-views.
It is important for an SEO page to contain just enough keywords. Too few keywords and the page will not rank highly when popular phrases are searched on Google, Yahoo, Bing, and other search engines. Too many keywords, and the search engines will disregard the page altogether as spam. A good keyword density is typically about 3%.
Social media optimization includes important SEO keywords, but it also envelops a number of other practices for site optimization. Most notably, SMO gains increased site traffic by using social media tools alongside SEO best practices. Social media, such as Facebook, Twitter, Myspace, Wordpress, and LinkedIn, is any online media that encourages active user dialogue, photo exchanges, or link sharing.