A search engine or crawler engine searches the world wide web and looks for information that a visitor has asked for, they do this by linking the relevant keywords and unique content to the information requested.
Websites are created for the purpose of offering information to the viewer by way of a visual and audio medium. This is the reason that search engines were developed.
For search engine optimization to be of benefit to your website, it is important for your site to have a high search engine ranking, if possible in the first ten top placements. This is because most visitors to the Internet search for information in the top ten websites.
Many search engines have introduced paid advertising this means that web owners have the option to pay for advertising on the most popular high ranking relevant websites. The most popular example of this method is Google AdWords.
Engine optimizing started around the mid 1900s they used a cataloging system and web masters had to submit websites to different search engines to be able to grab the attentions of engine spiders. The spiders brought all the information needed to the search engines.The engines would show the websites according to topic when the keyword or topic was searched by the visitors.
Webmasters used meta tags and these were identified by the engines,but this system was abused so other more complex systems had to be devised. The new systems that were put in place developed other strategies such as text content, latent semantic indexing, domain name, Titles, keyword density and a host of other factors.
Today it is a whole new ball game and it is very hard if not impossible to fool the search engines because of the new technology being used.