A
lot of Content and Links displayed on a webpage may not actually be
visible to the Search Engines, eg. Flash based content,
content generated through javascript, content displayed as
images etc.
This tool Simulates a Search Engine by displaying the contents of a webpage exactly how a Search Engine would see it.
It also displays the hyperlinks that will be followed (crawled) by a Search Engine when it visits the particular webpage.
See
Your Site With the Eyes of a Spider
The article explains how Search Engines view a Webpage.