A ‘hard 404′ is the code and the message we’ve set up to appear when a URL is requested that our website server cannot supply. That’s the way a website should work. It’s quite different to a ‘soft 404′, which is a message on the website saying that the page can’t be found, but behind the scenes is still actually a proper page which can be indexed by the search engines.
Google describes a ‘soft 404’ as “a URL that returns a page telling the user that the page does not exist and also a 200 (success) status code. In some cases, it might be a page with little or no content (for example, a sparsely populated or empty page).”
As far as SEO goes, soft 404s are bad. If we have lots of URLs like this, the search engines will try to index them all as separate pages, and then just see lots of identical pages with the same very ‘thin’ content.
The way to handle pages that have gone away is to use a 301 redirect (see yesterday’s article) or to set up our site so that they return 404 or 410 codes. Some experts don’t like the idea of 301-redirecting expired product pages to their replacements, but it’s fine if done well. As ever, think of it from the user’s point of view: if they visit bluewidgetcompany.co.uk/oldwidget and are silently taken to bluewidgetcompany.co.uk/newwidget without explanation, it could be confusing. But if the new page mentions that the new widget has replaced the old, that makes things clear to customer and search engine alike.