SEO (Search Engine Optimisation) is the practice of increasing a website's organic visibility, within search engines. This is currently made possible by an amalgamation of, on-page and off-page optimisation. 

Having a effective SEO strategy, will have your website ranked highly on page 1 for keywords that a profitable for your business. The result of these rankings is not just increased traffic, but importantly, better quality traffic.

Better quality traffic = highly targeted leads or sales.

SEO  stands for Search engine optimisation, that is the process of affecting the visibility of a website or a web oage in a search engine's result.

Everything you need to know is right here:

http://www.katetooncopywriter.com.au/faq/seo/ :-)