Search Engine optimization (SEO) is a cumulative result of a number of factors which basically can be summarized into two categories: On page optimization and off page optimization factors. One of the key factors pertaining to on page optimization is making sure that your website structure is search engine friendly so that search engines can properly spider and index your site. Two most important things in this regard to be remembered as a rule of thumb are:

1) The links in the site must be true hyperlinks that can be picked up properly by the search engines: Hyperlinks generally tend to serve two purposes: First it helps the search engine to properly spider the site and second helping to increase the page rank of your site. For example if you have 80 sub pages and all of them contains a link back to the home page of your site then in the eyes of Google you receive 80 votes for your website, which facilitates in increasing your overall Page Rank. Often people tend to disregard this fact and use "non-standard" hyperlinks. "Non-standard" hyperlinks are javascr'pt generated hyperlinks or hyperlinks embedded within flash files. The simple fact is that javascr'pt and flash is NOT search engine friendly and this factor is a major hindrance to SEO. Google is pretty much the only engine that is able to pick up links within javascr'pt or flash code; however it is unclear whether Google places any VALUE on the links it finds in this manner. At present either Yahoo or MSN does not have this ability. So, be absolutely sure that your links are true hyperlinks ("true" hyperlinks are hyperlinks coded with the normal "href" tags), if you want to get your site indexed and follow proper SEO techniques.

2) All main pages or first pages, within the site are reachable within 2-3 clicks from the homepage: Ideally, you want your visitors and the search engines to be able to reach any main page within your site preferably within a maximum of 2-3 clicks. The more clicks it takes to reach a page, the less chance there is that the search engines will index that page. It is for this reason, that site maps have become so popular. By utilizing a sitemap, you are able to link from your homepage to a page that lists all or most of the links to the various pages of your site. The search engines (and visitors) are then able to get to virtually any page of your site within just a couple of clicks. However it is important to remember that site maps are not a total fix for bad navigational structure within a site.