A 404 error is a “file not found” error that displays is someone mistypes a URL for your site or tries to visit a page that does not exist. 404 error pages can be very useful and there are many ways that 404 errors can be handled. Ultimately, they are part of a website, contributing to site structure and user experience, which can affect rankings within the search engines. It is important, therefore, that 404 errors are handled correctly.

A soft 404 error is one method of handling these errors, but is not recommended by Google. A soft 404 error does not display a “page not found error” but instead it redirects the user to an already existing page (usually the home page). Google is not keen on this method of handling 404s for two reasons. Firstly, it can be confusing for the user, who doesn’t understand why he has been redirected. Secondly, it can be confusing for search engine spiders and, in some cases, can cause duplicate content issues.

Soft 404 Process

Instead of using soft 404 errors, it is advisable to serve genuine “hard 404″ pages, that inform users that they have tried to access a non-existent page. In fact, it is possible to improve 404s by giving suggestions of correct pages, which will help users navigate your site if they stumble across a 404 error page. This is done by using a piece of javascript, examples of which can be found in Google’s webmaster tools.