There are various ways to approach SEO. In the industry, there are many different philosophies and tactics that SEO companies may use. These fall under three categories: White Hat, Gray Hat, and Black Hat.
White Hat techniques include creating a quality website, constant and organic blogging, internal linking, and creating quality content. White Hat SEO strategies stick to Google’s published guidelines and is considered to be ethical search engine optimization. However, white hat SEO does not produce immediate results; but when it does they are often very long lasting. It may take a while, but it is worth it. Unlike Gray or Black Hatting, White Hat SEO does not result in potential consequences or penalties from search engines.
Read more here: http://www.seolosangelescity.com/good-vs-bad-seo-strategies/