atlrus - 11:25 pm on Jun 18, 2013 (gmt 0)
Uhm... Have you entirely missed several years of discussion of the "soft 404" concept?
I must have, where did this discussion took place? Here is what Google itself says about "soft 404", bold is mine:
Returning a code other than 404 or 410 for a non-existent page(or redirecting users to another page, such as the homepage, instead of returning a 404) can be problematic. Firstly, it tells search engines that thereís a real page at that URL. As a result, that URL may be crawled and its content indexed. Because of the time Googlebot spends on non-existent pages, your unique URLs may not be discovered as quickly or visited as frequently and your siteís crawl coverage may be impacted (also, you probably donít want your site to rank well for the search query [File not found]).
I admit I don't keep up with protocols as often as I should, but I am sure I, Google, W3 and the rest would have not missed a change in 404. If there is a special WebmasterWorld meaning behind soft 404, then no, I don't know about it.
Google knows very well what they are doing - sticking their nose again where it does not belong.