White hat and black hat SEO are industry specific terms that describe ethical (white hat) vs. unethical (black hat) ways of optimizing a site. Black hat SEO is like the dark side of the force - it might look tempting and achieve fast results, but it can get your site permanently banned from search engines. White hat SEO is the ethical approach to search engine optimization that achieves results through processes that search engines recognize as valid. Like Jedi-training, some white hat SEO techniques can take time, but it is worth the wait. As an example of black hat, a website could use keywords repetitively in the same color as the background. A search engine would see this in the code, but users would not. If search engines find out, they can unlist and ban your site. The ethical way of using keywords on your site is to increase interesting and relevant content that can also be posted in blogs and articles to link back to your site.