Webmasters and content providers began optimizing websites for search engines in the mid-1990s, as the first search engines were cataloging the early Web. Initially, all webmasters only needed to submit the address of a page, or URL, to the various engines which would send a "spider" to "crawl" that page, extract links to other pages from it, and return information found on the page to be indexed. The process involves a search engine spider downloading a page and storing it on the search engine's own server. 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. All of this information is then placed into a scheduler for crawling at a later date.
When referring to the homepage, a trailing slash after the hostname is optional since it leads to the same content ("https://example.com/" is the same as "https://example.com"). For the path and filename, a trailing slash would be seen as a different URL (signaling either a file or a directory), for example, "https://example.com/fish" is not the same as "https://example.com/fish/".
The Internet and social networking leaks are one of the issues facing traditional advertising. Video and print ads are often leaked to the world via the Internet earlier than they are scheduled to premiere. Social networking sites allow those leaks to go viral, and be seen by many users more quickly. The time difference is also a problem facing traditional advertisers. When social events occur and are broadcast on television, there is often a time delay between airings on the east coast and west coast of the United States. Social networking sites have become a hub of comment and interaction concerning the event. This allows individuals watching the event on the west coast (time-delayed) to know the outcome before it airs. The 2011 Grammy Awards highlighted this problem. Viewers on the west coast learned who won different awards based on comments made on social networking sites by individuals watching live on the east coast. Since viewers knew who won already, many tuned out and ratings were lower. All the advertisement and promotion put into the event was lost because viewers didn't have a reason to watch.[according to whom?]
Optimizing a website may involve editing its content, adding content, modifying 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.