Search Engine Optimization refers to increasing your Page Rank for a higher position on FREE online searches. Google and Yahoo for example have two display areas for all the search results: A Organic Search results area and a Sponsored Search results area.
The sponsored search (also called PPC = Pay Per Click) will show web sites that are paying for the click. Google and Yahoo for example will charge every time someone clicks into the web site submitted. The sponsored search web sites will show on the top and on the right of the search results. This is called Paid Keyword Advertisement. Depending on the Keyword, a click usually costs anywhere from $0.20 to $1.50 or even more.
The organic search is the area on the left and clicks there are not charged, if your web site shows in the organic search area you could get a very large amount of traffic totally free of charge. But how can you be there? Well, probably everyone who has a web site wants to stand on top of the organic search area and get all the traffic for free. What determines which web sites will show first on the free area is the Page Rank (PR) and to increase your PR you need what is called Search Engine Optimization.
The picture above shows an example of search results on Google, the area within the blue border is the sponsored search area and the one within the orange border is the organic search area. On the picture below you can see the same areas indicated on a regular Yahoo search.
All web crawlers have submission pages where you can submit your website URL so it will be added to their indexes and will appear on future searches.
Every crawler has its own indexing softwares that are generically called Robots. One of the Robots function is to constantly trace the internet for new contents and eventually these robots would trace your web site. But it might take very long until all robots from all crawlers find you, therefore submitting your site manually is important to speed up the process.
The two most important crawlers are Google and Yahoo. I would say that they represent at least more then 95% of all the searches online. But it is still important to submit your site to all crawlers because this will eventually help you to increase your Page Rank.
The DMOZ Open Directory (dmoz.com) is also a very important resource to be considered. it is one of the long time resources on the Internet, a human edited thematic collection of resources, and the base data of the Google directory itself. DMOZ is a very interesting project with volunteers that will exam every submission before it gets authorized making it the most accurate and reliable crawler available.
Other then the major crawlers there are also several topical directories and smaller business directories that will accept free submissions as well and these should definitely be considered. Even if they have low PR they will provide reasonably relevant external links (links to your page) and help building your page rank.
Once your site is submitted it will show on searches on the organic search area but not necessarily, and most likely not, at the top of the page. Probably not even at the second page, neither third. It might show at the last page or still not even show at all because the crawlers usually show a maximum of 1000 results and if there are 1000 sites submitted under the same keywords with better PR, you will not be shown.
Now, if someone makes a search using a keyword that is very unique to you, for example, your web address or your very own name or your business name, chances are you will show on the top of the search within 30 to 90 days after submission. Well, at least that must work. Therefore submitting your site is very important for people to find you once they know your name. Some businesses cannot be found on the internet even if you search for their names or their web address and that is unacceptable!
Obs - It is prejudicial to submit URLs already submitted, therefore check if your URL is already indexed by each crawler before submitting. These buttons represent the major crawler's network only, there are more then 5 thousand directories that a URL could be submitted to, which would create a considerable increase of popularity. You can use the Free URL Submission Tool to make extra submissions. Never use automatic programs to submit URLs. URLs should ALWAYS be submitted manually, do not trust ANY submission software!
The most important thing of any web site is, of course, content. Providing relevant, unique and quality content is fundamental for success because search engines are all about indexing content. And it is known that the robots can detect quality content very well.
The content must be unique. If you copy contents from other web sites the crawlers will most likely ignore it. Google uses a filter to sort out duplicate content and battle off plagiarism and scraper sites, and, of course, to provide higher quality search results. Web sites with content that can be found on another web sites as well are being lowered in their importance, and eventually are turned into supplemental results.
It is ok to copy content as long as it doesn't exceeding a small percentage of the total unique content.
Unique content means a content that is not indexed and, basically, to get unique content there is only one way: WRITING IT! And not purchasing or copy and pasting it.
I have constantly received emails offering content for sale which will absolutely not help you.
I have seen myself some clients who told me they had recently purchased and installed content that will help them on optimization and I was immediately able to show them how the results were already marked as similar irrelevant pages on google.
Having those pages is not so good, better of without them.
The content should also match what is called "Keyword Representation". You can read more about it on the Keywords page.
It is also important to remember that the only content that search engines can read and index is the coded text. Text in images cannot be read by the robots neither text in flash contents. It is also important to use all the code resources to arrange the written content properly so the search engine robots can easily index it. You will see more info about this on the Search Engine Friendly Code page.