Description META tag:

In past this tag was used to specify text that would appear in search engine results alongside link to your site. Keywords could be placed into this text to influence ranking. However it was abused similar to Keywords META tag and has befallen same fate, meaning it is not as useful as it once was. Some search engines do not display it in their results (most notably Google, which retrieves text from content on your page) and do not use it to rank a site. Having said that some search engines do still use it so again it is a mistake to ignore it completely.

Descriptions placed into this tag should, strangely enough, be very descriptive of page or site they reside in. Include a few relevant keywords/keyphrases that you are optimizing for in description and try to limit its length to 25-30 words. Also try to use no more than two sentences.

Summary:

Although not as important as they once where, META tags can still influence a search engine when it comes to deciding whether your web page is relevant or not.

Keywords META tag:

15-20 keywords, include misspellings of keywords/keyphrases

Description META tag:

Include keywords/keyphrases, 25-30 words, no more than two sentences.

* Complicated menu systems *

Search engines spiders that crawl through our pages are a relatively primitive bunch. They find in hard to navigate complicated menu systems implemented for example in JavaScript or as a Java applet. Just because it is easy for a human to navigate through site never assume it will be as easy for a search engine spider. A menu system using simple textual links will be easier for a spider to understand and it will be able to successfully navigate your site. A lot of time complicated menu systems can be replicated using textual links and CSS.

If you must use a complicated menu system be sure to provide a site map that is clearly accessible from homepage of your site and contains only textual links to your pages. This ensures that even if spider cannot understand your menu system that it will be able to find pages on your site.