Hi,
Apologies if SO is not the right place for this, but there are 700+ other SEO questions on here.
I'm a senior developer for a travel site with 12k+ pages. We completely redeveloped the site and relaunched in January, and with the volatile nature of travel, there are many pages which are no longer on the site. Examples:
/destinations/africa/senegal.aspx
/destinations/africa/features.aspx
Of course, we have a 404 page in place (and it's a hard 404 page rather than a 30x redirect to a 404).
Our SEO advisor has asked us to 30x redirect all our 404 pages (as found in Webmaster Tools), his argument being that 404's are damaging to our pagerank. He'd want us to redirect our Senegal and features pages above to the Africa page (which doesn't contain the content previously found on Senegal.aspx or features.aspx).
An equivalent for SO would be taking a url for a removed question and redirecting it to /questions rather than showing a 404 'Question/Page not found'.
My argument is that, as these pages are no longer on the site, 404 is the correct status to return. I'd also argue that redirecting these to less relevant pages could damage our SEO (due to duplicate content perhaps)? It's also very time consuming redirecting all 404's when our site takes some content from our in-house system, which adds/removes content at will.
Thanks for any advice,
Adam