Crawl Errors now reports soft 404s
«Webmaster Level: All Today we’re releasing a feature to help you discover if your site serves undesirable “soft” or “crypto” 404s. A “soft 404″ occurs when a webserver responds with a 200 OK HTTP response code for a page that doesn’t exist rather than the appropriate 404 Not Found. Soft 4…» » source | + cache
See original post by Chris Gilmer