The SEO arena is unstable and ever changing. With every Google update (e.g. Panda) the SEO world becomes affected. Some businesses go under, others rise up and new theories and SEO strategies come up. SEO is simply about getting a site or a blog to rank first in Google searches by staffing specific keywords in the site. The problem with SEO at the moment is that many sites in a bid to rank first on Google searches have neglected the quality of their content and Google are out to change this, one update at a time.