Gray hat SEO is the use of unethical SEO tactics that skirt the line between what is considered "white hat" and "black hat" SEO. Gray hat SEO practitioners often employ tactics that are frowned upon by Google, such as article spinning, link buying and link building from low-quality websites. However, they stop short of actually breaking Google's rules, which can lead to penalties from the search engine giant. For this reason, gray hat SEO should only be used as a last resort, as it can quickly lead to website rankings dropping like a stone. If you're looking for long-term success with your SEO efforts, it's best to stick with white hat tactics and avoid any gray area altogether.