Keyword Stuffing
When the Web was young and search engines were starting to gain in popularity, some smart website owners realized that the search engine Algorithms really liked some Meta Tags. Really liked them. So they started stuffing a bunch of keywords, often with high search volumes and no relevancy to the site, into the title, description, and keyword tags. Sites instantly rocketed to great SERPs. Soon thereafter the search engines changed their ranking formulae and the sites lost their positions or were outright Banned.