You've probably heard of SEO, since it's very hot right now. It stands for Search Engine Optimization. SEO is the process of increasing the amount of visitors to a site by designing the site content so that the site ranks high in the search results of a search engine.

The higher a Web site ranks in the results of a search, the greater the chance that a user will visit that site. Let's face it, most people are lazy. They're not going to spend time clicking and scanning tons of pages of search results. Therefore, where a site ranks in a web search is absolutely critical for directing more traffic toward the site. SEO helps to make sure that a site is accessible to a search engine and improves the chances that the site will be found by the search engine.

To understand how this works, you need to know a little bit about how search engines work. Typically, a search engine sends out a spider to fetch as many documents as it can. Then another program, called an indexer, reads these documents and makes an index based on the words each document contains. Each search engine uses a unique proprietary algorithm to create indexes so that hopefully only meaningful results are returned for each query.

These indexers compute the keyword density. Keyword density refers to the how often a certain word appears in a given document. It's given as a percentage. Let's say you have a site about running shoes. A keyword density of 7% on "running" on that web page means that out of 1000 words, 70 of them are "running."

Unfortunately, the quick-buck con artists have figured this out, and they will put up a site that has a front page that is totally littered with keywords. To give you an idea, a normal key word density for the main key words is about 3 to 7%. What these people will do is have something insane like a 25% keyword density on their front page. Then that page ranks #1 in search engine results when users search for that word. Once the user is on the entry page, they're likely to enter the site.

Pornographers do this by putting up sites that have content like:

Sex, sex, sex. Sex is here. You want sex. We have sex. Pix of sex, lots of sex.

See how annoying that gets? Search engines used to use meta-tags to search for web sites. This was nice, since the meta-tag was a hidden area of your page where you could put all the relevant keywords and not have to worry about making your content sound awkward by overusing certain words.

Things to Consider There are many things to consider when you go to put keywords in the text of your pages. Most search engines index the full text of each page, so you should put your keywords throughout your text. However, each search engine uses different ranking algorithms. And that's the really hard part--difficult though it may be, you need to keep all of them in mind.

General rules Your main page should be full of keywords because that page has a higher chance of being indexed than other pages. And for some search engines, it will be the only page that is indexed.

Some engines will rank your page highly if it has at least 100 words on it, so consider that your minimum. Directories include pages based on the quality of their content, so make sure your pages aren't just lists of keywords. If you do that, you risk not getting in the big directories AND you will irritate readers-they won't come back.

Important design concepts When you create your pages' content, pay attention to:

Keyword prominence Proximity Density Frequency

The thing about keyword prominence is that the best place to place keywords in your text is at the top of each page, preferably the main page. The closer your keywords appear to the start of the page or the start of a sentence, the better. You'll frequently see "keyword prominence" used to describe search engines' algorithms. Be aware that some engines also say the bottom of the page should contain keywords as well