Understanding SEO. What is and why you need SEO? Why do you need SEO? It's all about marketing your website. 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. So, you need some sort of advertising in order to attract customers and visitors. You can use offline advertising such as word of mouth, fliers, newspapers and TV ads, etc. but usually the conversion rate is very poor and the costs are high. Online advertising on the other hand is more appropriate because through online advertising you get targeted web traffic, so you have higher conversion rates and lower costs. A great deal of the web traffic you get is driven by the three major search engines: Google, Yahoo and MSN, because entering search queries in the search engines is a primary method of navigation for most of the Internet users. So it's obvious that it is desired to have your website coming up in the search engine results pages (SERP). With millions of websites out there, users usually check the first couple of results pages, so it's important that your website is listed in those pages. You can do that by "buying" yourself a place in the sponsored links area or, showing up for free, through "organic" results. 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. Although there are some "black hat" SEO practices that you can use to manipulate search engines to achieve high rankings, this article and the next ones will only talk about "white hat" SEO practices used to create relevant websites that search engines and users will be happy to rank them in the top positions. Understanding SEO 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. Your Friendly Search Engine Spider search engine spider 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."