White Hat SEO - In this method you have to follow all the rules for promotion created by search engines. This method takes time to get good position but the site position will be static. This is also known as ethical SEO. (like:Proper and appropriate Keyword Stuffing, Meta tags, header tags, relevant alt image tags ,tittle tags, use of proper anchor text, Link Building, Directory Submission).
Black Hat SEO- You do not need to follow the rules start promoting your site randomly. This methods can put your site in top very soon in search engine but the position will not be static. Your site may be banned by major SEs. (like:Spamming on discussion forums, irrelevant Blog commenting, too much keyword stuffing, distributing Virus/Worms or promoting infected sites).
Its always advisable to adopt Ethical SEO techniques.
Blackhat SEO is any unethical way of promoting your site or any way of trying to fool the search bots. It isn’t a topic we generally like to explore around here. But if you use the native forum search or try [URL=“http://search.sitepoint.com/”]SitePoint’s advanced search, I’m sure that’ll yield the info your looking for.
You could also try a Google search for Blackhat SEO.
White hat seo is the kind of seo that you perform and don’t think twice about doing it
Black hat seo is the kind of seo you do and you actually think twice about doing it and your there on the border line thinking, hmm, is this grey hat or black hat, whilst you know deep down its black hat
In nutshell if try to promote your site by means of adding content useful to your targetted audience you call this as white hat technique. When you build link farms with effort to just influence the search engine it will lead to black hat technique.
Blackhat SEO should never be used. At best, it’s unethical and at worst, it may result in a ban placed on your site from Google.
If you stay away from any trickery and optimization specifically for the search bots and optimize for your real users, then you’ll be fine.
White hat seo is the ethical way to promote the website. Where we follow the rules and algorithms of the search engine but black hat seo is just opposite the white hat seo.