We've redesigned one of our sites and have orphaned several thousand pages which we know are indexed by the search engines. The functionality simply does not exist anymore. Are we better off 301 redirecting all of those pages to the home page, or delivering a 404 page with links to the new sections of the site? A 404 is 'proper,' of course, but for SEO purposes should we use the 301 instead? Anyone?
I definitely 301 is good for you in this situation, you will keep ranking on new pages after you change the links
I'd go for 301. Any ranking value can then be passed on. If you have thousands of pages, then it will take time, but will be worth it. Also i'd work on your 404 page, just in case you miss out some of those pages, for what ever reason.
Hold on. I need to ask you something in return. Did you simply flat out remove these pages, or were they moved to a new location? If they were flat out dropped, return a 404 error and have that error generate a user friendly error page, such as the one below: Otherwise, just redirect the old URL to the new one.