The main reason to apply search engine optimization techniques is to increase your web site's traffic by obtaining higher rankings in search engines for keyword searches related to your web site. The idea is that with increased traffic, you will have increased sales.
You can also increase your traffic exponentially by getting high rankings in search engines. For example, if you currently have 100 visitors per day, and managed to effectively increase your traffic to 1,000 visitors per day, you would notice your traffic increasing each month. There are several factors which can contribute to this phenomenon. One of them is referred to as "viral marketing". Although a somewhat ugly name tag, it describes the type of marketing which has exponential growth. Back to our example, if 10% of your visitors passed your domain name onto their friends or co-workers, or established a link to your home page, you would see an alternative source of traffic to the search engines. This is the basic principle behind "word-of-mouth" referalls, and holds true with links.
In an effort to increase your viral marketing potential, it is a good idea to provide a "links page" where people can exchange links with your site. You should also include several html code snippets that visitors can simply copy-n-paste into their own html pages on their sites. In doing this, it is highly recommended you use your targeted keywords for your homepage in the link exchange code you are going to provide on your "links page". You can read more about link exchanges in the Link Exchange chapter.