1. Tables - You're most likely familiar with what a table tag looks like. They generally look like this <table width="100%" border="0" cellpadding="0"> or some variation, right? There are actually two areas within a table tag that keywords can be applied to. The table ID and Summary. A table tag written in this manner will look more like this <table width="100%" border="0" cellpadding="0" id="Accommodation Rates" summary="A breakdown of rates for Accommodations at Estancia Los Protreros">.

2. File Names - HTML, images, CSS files, php scripts, cgi scripts, asp scripts, java apps, video clips, sound bites, and every file you use to create your web site can be named using keywords that apply to the web site content. Making sure these titles also apply to the purpose of the file itself is also very important, especially if the file type can be indexed by search engine bots, like php and flash. If the name of the file has very little to do with what the file contains, it will have little to no affect on your keyword density.

3. Reference Tags - A normal reference tag looks like this <a href="http://www.ride-americas.com">. A title can be added to this tag making it look like this <a href="http://www.ride-americas.com" title="Horseback Riding Vacations in Argentina">. This can also be applied to mailto: reference tags. Because this text will be seen by web visitors when they hover their mouse over the link, it's good practice to keep it relevant and to-the-point. Never sacrifice user-friendliness for more keywords. You may get lots of traffic with the keywords, but without user-friendliness, that traffic will leave displeased.

4. Comment Tags - I thought everyone knew this one, but I haven't seen many sites out there making use of it. Comment tags are generally used to remind us of what the following or preceding code does, like little HTML post-it notes that can only be seen in the source code. They look like this <!--Horseback Riding Accommodations Rates Page--> where everything between the "<!--" and "-->" is the comment or note we're leaving ourselves. Used wisely and in moderation, this can be yet another opportunity to add keywords to your site's source code.

All of these areas are good areas to add keyword density to your site, but they all must be used with caution. Everything in these areas should be in context, meaning they should relate directly to what a web visitor will be seeing. They should also be used in moderation. Strings of keywords in a table summary tag will surely start raising some flags at the Googleplex. It won't be long now before Google and other major search engines start keeping a closer, more critical eye on these areas. The most important rule of thumb to go by when designing and optimizing any web site, is to keep it user friendly. A pleased and impressed web visitor is the best web site optimization and will surely lead to your site's success.

Courtney Heard is the founder of http://www.abalone.ca, an Internet Marketing and SEO company in Vancouver, Canada. She has been involved in web development and marketing since 1995 and has helped start several businesses since then in the Vancouver area