Forum Soft 404 Errors in Google Webmaster Tools
 

We've historically had a large number of spam signups which were all placed in the Banned usergroup. A couple of months ago, we purged these old banned users as we knew they would never be returning.

Since this was done, Google has been emailing us reporting a significant rise in "soft 404" errors for "member.php" containing the deleted user ID, see below for an explanation:

http://support.google.com/webmasters...&answer=181708

As Google explains, when a page does not exist it should return a 404 response code. The problem with vBulletin is that it almost never issues a 404 response code.

All of the deleted user URLs return a 200 OK response code, which is clearly not correct. A 200 response means that the URL request found related content, a user which does not exist is not valid content and should not be indexed. I appreciate that there is a "noindex" meta tag on the page, but Google still treats this as a "soft 404" and is not happy about it.

Many of these spam user accounts were linked to from other external sites, so these incoming links are not going away. We need to return a 404 error page for pages that do not exist.

I hope you agree that this is the only correct response.