How do Search Engines Work?
There are 3 areas in the search process of an engine: bots, indexes, and queries. Search Engines involve two main parts: a bot and an index. Search Engines use bots to index sites. These are automated programs run by the search engines. The indexing can happen either by following a link or a submission request. Basically a crawler is capable of scanning the content of a site from the meta tags and navigation, to the copy content, and following any internal or external links available. Then this information is sent to a datacenter for further processing, and final indexing. As information changes, the bot will keep visiting the site for these changes on a given interval that is different from one site to the other. So, when you query the engine with your search, the results are pulled from the index, in order of relevancy according to the search engine algorithm.

What is Search Engine Optimization?
If it can be resume to a word" SEO is a process. It starts by selecting the most targeted keyword phrases for your site, and it never ends. You will always need to maintain those hard earned ranks for your site in the search engines. In the middle, you will need to optimize your meta tags and content along with building appropriate related quality links. You noticed I mentioned the "Big 3". By that I mean in order of market share: Google, Yahoo, and MSN. To serve the most relevant, spam-free results, search engines keep their algorithms secret, and they differ greatly as well.

Why do Search Engine Optimization?
When 90% of web users use search engines to find what they are looking for online, and with 65% of them clicking on organic (non-paid) results when analyzing the top two pages of results, having a top search engine ranking really make the difference between online business success and failure. The best part about using SEO is that the traffic you will get as a result of having search optimization is free. Free traffic is the best traffic you can possible get and since your site is optimized for it, the traffic you receive will be highly targeted, because the people are searching for what you are optimizing for.