lucy24 - 9:18 pm on Jun 21, 2011 (gmt 0)
When the page is archived on our site (should correspond to the meta), then I'm going to put a 410 on the page (I can't find a huge amount of information on implementing 410's but Google seems to suggest it for permanently removed content)
The 410 is done in a counter-intuitive way, by redirecting or rewriting to nowhere:
[httpd.apache.org...] (scroll down to "gone|G")
Here it sounds as if you want to send users to a different 410 page for each no-longer-used primary page, so a 301 may be safer.
Make sure search engines do not get one single 404 before you get the 410 working, or they will keep trying to crawl the no-longer-there page forever. If they get a 410 right away, they will learn pretty fast.