JD_Toims - 3:00 pm on Jul 30, 2013 (gmt 0)
- What would be the impact on Google rankings when it suddenly starts finding a huge number of 404 errors.
The algo already sees them that way. Soft 404 means they're being treated as 404s even though a proper 404 header is not being served.
Personally, I would "do it the other way around", meaning serve a correct 404 or 410 header for the removed pages but rather than a generic 404/410 error page I'd grab and display the information that would be redirected to on the 404/410 page for visitor convenience. (I would also noindex the 404/410 page, just to be safe.)
ADDED: I'd probably insert a "sorry, that page has been removed, but we've provided you with similar resources below." notice at the top of the error page so visitors know what they were looking for is not present, but there are other resources on the site they might like.