Google Webmaster tools have for a long time had the option to create custom 404 pages. If you are unsure on what 404 pages are then you should have a quick read of them here. I have always been a fan of the custom 404 page which basically allows the 404 page to display the template of your website with only the content area changing. Within the content area you would place the message “Page not found” or something similar, but crucially it allows you to add a search feature where a user can navigate through the website to find something relevant to their initial search.

I’m a bit of a hypocrite with this as I don’t always do it, as you can see on this blog! However that is mainly due to the fact that I used a WordPress template and everything is kinda done for you – no search feature this time though. Something else you can add is an internal HTML sitemap for inner pages so the user can choose from any of these, just as easily as searching for something they want.

The beauty of the custom 404 page is in the name. It really is custom and you can tailor it to suit your users. Find out your most popular pages or posts and offer links to these, and of course, add the search box. Webmaster forums has a page which shows you how to do this for your site here.

In terms of SEO, there is no harm in not having custom 404 pages, as long as you locate your 404 pages and redirect them before they get found by Google (and other search engines). It is more a case of usability and user experience. It offers alternatives and you are more likely to keep users on your site by using this method.