Joe Whyte wrote a nice article on Optimizing your 404 error page, with these tips.

1. Put a link to your FAQ page
2. Put a link to your top level categories
3. Put a link to your sitemap
4. Create a templated 404 page that blends with your site
5. Add a search box
6. Make your 404 pages look as close to your site theme as possible
7. Add a true navigation to your site.

However, as usual, I think there are certain things you can also include:

1. Ensure your error page still returns a 404 to a crawler.
   • Some blogs and CMS systems return 200 codes (found) which confuse the crawlers as to legitimate content on your site.
2. Look at the URL (or referring keyword) and then serve up search results based upon that information.
3. Serve related articles to the search term.
4. Remember your website goals!
   • You may wish to slant your 404 page towards retail, newsletter signups, subscriptions, etc.

I agree with Joe’s statement “One of the most overlooked SEO techniques is optimizing you 404 error pages”.

Joe’s article at Search Marketing Standard.
Joe’s blog at joe-whyte.

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