For better keyword ranking SEO would be great helpful.In SEO there are some techniques you use.Those are 1.Social bookmarking 2.Directory submission 3.Blog commenting etc.In these techniques we use keywords so that we get better ranking.
Organic SEO is based more on keywords in blogs, back linking, localization services (Google Places) and webpage design, while SMO is based more on postings on social media sites. While both are considered important, SEO has traditionally been considered much more important.
SEO takes a longer time to show results. Whereas SMO is more quick and concrete in terms of results. SEO does not connect you to your potential customers but SMO is customer friendly. In the sense that by using SMO, one can connect to customers, share information and even gain feedback.