Hope someone can shed some light on the best way to do this. We currently have a website with roughly 3 1/2 million pages indexed into google. Now we've decided we no longer need this site and we're taking it down and replacing it with a much smaller (totally different) site on the same domain.
So the pages that are already indexed i would like them all to direct to a single page explaining what's happened to them. (if that makes sense).
So for arguments sake lets say the site i want to remove all pages for is 'xyz.com' so if someone clicks on an indexed page e.g 'xyz.com/indexed-page/' i want that to go to a new page on 'xyz.com' let's say 'xyz.com/what-happened-to-indexed-page/'.
Now i'm guessing i shouldn't be doing 301's here because essentially i'm not moving the indexed pages, i'm actually removing them. So would it be best to just send all the current indexed pages to a custom 404 page and explain there what's happened to said indexed pages?
Hope that makes sense.
Thanks