Google's John Mueller said that Google may very well treat pages that no longer let you buy a product, i.e. the product is no longer available, as a soft 404. If you try to redirect that page to your home page, category page or an unrelated product, Google may treat that also as a soft 404. And Google treats soft 404s as real 404s and reports them in the Google Search Console.
As an FYI on that, soft 404 redirects are not really counted.
This came up in the Google Hangout on Google+ this morning at the 6:30 mark into the hangout. The question was:
Is it good idea to redirect pages with expired content (thousands of real estate listings) to help Google crawl more important pages? Even if these pages still have decent organic traffic (together about 10K per month)?
John Mueller responded:
So if these are expired pages where essentially the user is landing on a page that says we can’t sell you this product anymore, then that is kind of like a soft 404 page. which essentially should be treated like a 404 page. And if you have thousnads of these pages, then I wouldn’t redirect them unless I had a clear replacement for them. Just because this product that you are offering is not available anymore, doesn’t mean that it makes sense to redirect it to the home page by default.That is something where you really want to look at the individual situations and say, well is this other URL a really good replacement for the existing URL? Can I do a redirect and say this is clearly what we should be showing instead or is this essentially just a 404 that you are trying to do with a redirect.
And if you are essentially trying to do a 404 with a redirect, then what will happen is we will essentially pick that up as a soft 404 page. And say oh, the webmaster probably did this wrong, and we will just treat it as a 404 on our side.
He actually said Google treats these expired pages/products as soft 404s in the past, he said it in April. Of course, I know many SEOs who still use this practice of redirecting these pages to pass the link signals to other pages, but it seems like those link signals won't pass here?
Here is the video embed, watch it:
Forum discussion at Google+.
Update: Less than an hour after posting this, Glenn Gabe published his case study validating this.
