Search Engine Optimization (SEO) is techniques to bring more visitors from search results to your website/blog. But SEO is not only about getting free organic (search) traffic. You also need to understand how Google view (Crawl) your site, and how they index your site and how they rank your website into the search results. SEO is very simple if you know the basics. Also, many of companies move towards to SEO, because the advertising bid is getting higher day by day. SEO is not dead yet, but blackhat SEO will become harder in future. Here I will teach you mostly about whitehat SEO, and you should follow only white hat SEO because it pays off after a long time. In Blackhat techniques you may get the result faster, but one day Google will find that method and will destroy your business. You may get another technique after some time because there is always some balance between white and black, but I prefer white. Think SEO is like building an empire, you may struggle first, but there is peace for a long time.