Planet13 - 6:31 pm on Aug 14, 2010 (gmt 0)
I know of several websites that got into ranking trouble by 301 redirecting many pages to home (or a top level page of some kind) instead of returning a 404 or 410.
I have to ask you, how confident are you in that assessment? 50% confident? 75% confident? 100% confident?
I have about two or three dozen product pages where the product has been discontinued, so they 301 to the main category page for that product.
If you are certain of this, then I know what I will be doing this weekend...