For large web sites with extensive amounts of content, 2 to 10 percent of traffic is looking for pages that either don’t exist or have been moved. Most web servers return a generic 404 error page or a sitemap when a user’s desired page cannot be found. These unhelpful pages often result in a dead end for users.
With Microsoft’s Web Page Error Toolkit, you can create dynamic 404 pages that contain customized error messages along with search results seeded with relevant keywords to help your users move past the missing page and find the information they need.
The Toolkit is a customizable ASP.net application that replaces the default error page on your IIS server. The Toolkit enables you to use Live Search (or any search engine) to return results for the specified domain and locale, control the number of results returned on your page, choose whether to offer spelling corrections, and customize your error message.
You also have the option of choosing from several keyword extraction strategies that are included with the install, or providing your own implementation.
Get the Toolkit
To install the Toolkit, click WebPageErrorToolkitSetup.msi.
Before you install, review the API terms of service at Windows Live Platform and Services – Terms of Service.
Note: A new version of the toolkit was published on 8/26/08 to remedy a security matter found during an internal review. We recommend you download the new toolkit and recreate your custom 404 pages to safeguard the security of these pages.
[This information was originaly posted by Stephanie Horstmanshof]
An excellent article that helps in how to use it is Utility Spotlight Web Page Error Toolkit by Lance Whitney.