No matter if your website is an informational one or if it"s an online store to sell your products, you want people to come and visit it. Without visitors your information remains unknown and your products remain unsold. A great deal of the web traffic you get is driven by the three major search engines: Google, Yahoo and MSN, so it"s obvious that it is desired to have your website coming up in the search engine results pages (SERP). SEO, short for Search Engine Optimization is a collection of techniques and practices that will make your website show up in the first page(s) of organic SERP.
Now that you know what SEO is and why is needed, to better understand SEO you need to have an idea about how the search engines work. A search engine is a huge database of indexed web pages that users can query and get relevant results. So, a search engine needs to:
1. Crawl and Index Web Sites. Through automated scripts called robots or spiders, the search engines crawl through the Internet finding websites and web pages by following links and jumping from page to page and from website to website. Once a web page is crawled, its content is indexed into the search engine"s huge database.
2. Return Ranked Results. When a search query is made, the search engine"s algorithm finds out the pages in the database related to that query and returns the results sorted from the most relevant to the least.
Seeing how the search engines work, it is clear now that SEO will focus on the terms and phrases that users type into the search box and how to make your web pages relevant for those terms and phrases. But, because the Internet has become such a commercial place, the search engines have learned that they cannot rely only on websites to be honest about their web pages content. That"s why SEO needs to focus also on another factor used in ranking search results: popularity. Your web site is popular if others link to it. The more important the website that links to your website is, the "stronger" the link. A well-known system for ranking web pages is Google"s PageRank algorithm:
"PageRank relies on the uniquely democratic nature of the web by using its vast link structure as an indicator of an individual page"s value. In essence, Google interprets a link from page A to page B as a vote, by page A, for page B. But, Google looks at considerably more than the sheer volume of votes, or links a page receives; for example, it also analyzes the page that casts the vote. Votes cast by pages that are themselves "important" weigh more heavily and help to make other pages "important." Using these and other factors, Google provides its views on pages" relative importance."
So, to summarize, SEO is about building relevant web pages (Internal SEO) and making them popular (External SEO).