lucy24 - 4:52 am on Jun 19, 2013 (gmt 0)
if your ErrorDocument specifies a fully qualified url and causes a "404 response" to generate a 302/200 status chain, that's a "soft 404".
If your site intentionally redirects all bad requests to the home page, that's a "soft 404". It's a widely used technique-- and one that drives some human users up the wall.
410 Gone (or 404 Not Found) means the url is gone (or not found), not the product being sold on that url.
The query is part of the URL. That's why I said earlier that there's a difference between an "out of stock" label and a page that's empty in the middle.
Now suppose the bakery has never sold toasted coconut anything-- but it thinks that it might like to some day, and doesn't want to burn its bridges or turn away customers by saying it doesn't carry them, so instead it says day after day "We don't have any right now".
Besides, why is a site search pointing to an empty page? It ought to go though the intermediate stage of a search-results page-- which is no-indexed, so it doesn't matter whether there are any articles about widgets in Gambia.
If someone who knows the site's URL structure types in
and there's no such article, the request deserves a 404. And note again that this has absolutely nothing to do with what the human user sees. You can perfectly well make a custom 404 page that reads the query and says "I'm sorry, we don't have any articles about abc in xyz."