Black Hat SEO definition
Black Hat SEO:
Search engines set up guidelines that help them extract billions of dollars of ad revenue from the work of publishers and the attention of searchers. Within that highly profitable framework search engines consider certain marketing techniques deceptive in nature, and label them as black hat SEO. Those which are considered within their guidelines are called white hat SEO techniques. The search guidelines are not a static set of rules, and things that may be considered legitimate one day may be considered deceptive the next.
Most glossary items from Aaron Wall's SEO Book.
