Sullivan credits Bruce Clay as one of the first people to popularize the term. According to industry analyst Danny Sullivan, the phrase 'search engine optimization' probably came into use in 1997. 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. All of this information is then placed into a scheduler for crawling at a later date. A second program, known as an indexer, extracts information about the page, such as the words it contains, where they are located, and any weight for specific words, as well as all links the page contains. The process involves a search engine spider downloading a page and storing it on the search engine's own server. Initially, all webmasters only needed to submit the address of a page, or URL, to the various engines which would send a web crawler to crawl that page, extract links to other pages from it, and return information found on the page to be indexed. Webmasters and content providers began optimizing websites for search engines in the mid-1990s, as the first search engines were cataloging the early Web. 2.4 White hat versus black hat techniques.