A discussion of black hat and white hat SEO is as pointless as a discussion of the difference between black and white witchcraft. In witchcraft, the minute a technique is used to control the outcome of a situation it is known as black magic. The same can be said of SEO. A technique used to manipulate the search engines is known as black hat SEO. The problem is that white hat SEO does precisely the same thing so it is not any less “dirty” than black hat in some ways
An SEO tactic, technique or method is considered "White hat" if it conforms to the search engines' guidelines and does not attempt to deceive it. White Hat SEO is not just about following guidelines, but is about ensuring that the content a search engine indexes and subsequently ranks is the same content a user will see.
White Hat advice is generally summed up as creating content for users, not for search engines, and then make that content easily accessible to their spiders. It is more about user friendliness and accessibility rather than about tilting the odds seriously in one’s favor.
Black hat" SEO employs more deceptive methods to try to improve rankings. The search engines usually disapprove these methods. This can range from text that is "hidden", either as text colored similar to the background or by redirecting users from a page that is built for search engines to one that is more human friendly. As a general rule, a method that sends a user to a page that was different to the page described in the search is called Black hat. Search engines can and do penalize sites they discover using black hat methods, either by reducing their rankings or eliminating their listings from their databases altogether. Such penalties can be applied either automatically by the search engines' algorithms, or by a manual review of a site.