The Open Directory Project (ODP) is a Web directory maintained by a large staff of volunteers. Each volunteer oversees a category, and together volunteers list and categorize Web sites into a huge, comprehensive directory. Because a real person evaluates and categorizes each page within the directory, search engines like Google use the ODP as a database for search results. Getting a site listed on the ODP often means it will show up on Google.
As an Internet marketing strategy, SEO considers how search engines work, the computer programmed algorithms which dictate search engine behavior, what people search for, the actual search terms or keywords typed into search engines, and which search engines are preferred by their targeted audience. Optimizing a website may involve editing its content, adding content, doing HTML, and associated coding to both increase its relevance to specific keywords and to remove barriers to the indexing activities of search engines. Promoting a site to increase the number of backlinks, or inbound links, is another SEO tactic. By May 2015, mobile search had surpassed desktop search. In 2015, it was reported that Google is developing and promoting mobile search as a key feature within future products. In response, many brands are beginning to take a different approach to their Internet marketing strategies.