The 'keyword density cloud' was a nice little widget I worked on at work, to provide a graphical 'tag cloud like' analysis of the keyword density for a given web page. It can be used by SEO concious writers to quickly examine what a page of content may appear to be about (to search engines) based on the 'top words' and the relative strength of those top words, but is also a nice overview of the page content to end users. For example:
SEO Keyword Density by WMG

You can use the widget on any page that has a publicly accessible URL by simply pasting in the following javascript:
<div id="wmgcumulus">
   <!--This link needs to be included for the keyword density tool to work properly.-->
   <a href="http://www.webmarketinggroup.co.uk/" target="_blank">SEO</a> Keyword Density by WMG
   <script language="javascript" type="text/javascript" src="http://cumulus.wmg.uk.com/wmgcumulus.js"></script>
   <script language="javascript" type="text/javascript">
       DrawTagCloud(400,200,'ffffff','0x000000','0xc0c0c0',30);
   </script>
</div>
You can modify the parameters for 'DrawTagCloud', which are as follows: DrawTagCloud(width, height, bgColor, textColor1, textColor2, maxWords) Yes even I spell 'colour' as 'color' in code :\ As you may have guessed from the names used, the output is given using the WP-Cumulus WordPress plugin Flash component. Care should be taken when pasting the code into blogging software, such as Blogger, that no '<br>' tags are inserted into the javascript.