The early days of the internet were somewhat easy for website owners as putting a website online would take several months as it was very difficult work to build a site. In order to access the website a visitor simply had to type in the site address, or click a link that was included on a related site. Today nonetheless that is comparatively unimaginable, merely because of the fact that there are lots of millions, if not billions of websites available online. There are so many websites available on-line, that nobody really knows exactly how many there are at any one time, outstandingly since several hundred new websites appear each day.While this is excellent news for people reading sites, it becomes a challenge for website owners and publishers. After all of the determination, time and expense planning an on-line business, designing a site and uploading it to the WWW, it can be a disappointing thought to imagine that site is merely a single drop in a sea so large that it would be impossible to count the number of other drops.One of the most imperative parts of internet technology are the search engines. Someone searching for a topic would be unable to find the relvent data without the search engines. There are lots of search engines available to use but most people use Google, yahoo and MSN.But the question is still there, in that how do the engines decide which sites to put at the front of search results and which sites should be kept at the back? Early versions of these engines were little more than directories, categorised sections into which recommended links to suitable websites were placed. This meant a lot of work for the engines which had to manually approve every site.Today's search engines rely upon remarkably complex formulas known as algorithms. These algorithms are able to analyse the structure and content of websites and are able to identify the subjects, the keywords, and the likely relevance of that website as far as its subject matter is concerned. Additionally, these algorithms take into account the popularity of each website.You can liken it much to a voting system. The more people that are visiting that site means that it has greater popularity and more relevant content. In the same way, the more websites which link to this website, the more likely it is that it can be considered to be a reliable and trustworthy source of information.Knowing the ordinary ways in which the search engines analyze the content, context and popularity of websites, owners and publishers of websites are as you would expect very keen to guarantee that they maximise the chances of their site being considered important and helpful by a search engine. Achieving this is likely to guarantee the website appears near the top of the search engines results pages, creating a higher chance of supplementary visitors and probable customers seeing it.This is what is known as search engine optimization or SEO. Search engine optimization is the employment of methods and tactics which are likely to guarantee the site not only comes to the notice of the search engines, but achieves a high ranking location as well. Strong SEO is likely to mean supplementary customers, and is therefore an all-important part of making any online business successful.