In the early days of the web, site owners could rank high in search engines by adding lots of search terms to web pages, whether they were relevant to the website or not. Search engines caught on and, over time, have refined their algorithms to favor high-quality content and sites. This means that SEO is now more complex than just adding the right words to your copy.
Website owners recognized the value of a high ranking and visibility in search engine results, creating an opportunity for both white hat and black hat SEO practitioners. According to industry analyst Danny Sullivan, the phrase "search engine optimization" probably came into use in 1997. Sullivan credits Bruce Clay as one of the first people to popularize the term. On May 2, 2007, Jason Gambert attempted to trademark the term SEO by convincing the Trademark Office in Arizona that SEO is a "process" involving manipulation of keywords and not a "marketing service."