Imaster - 11:03 am on Jul 31, 2013 (gmt 0)
What is the average lifetime of these listing pages? Is it days? Weeks? Months?
It can be a couple of months to several years. Depends on how long a particular business is in operation. It's basically like a yellow pages site.
I don't think you should be doing that.
Google has said don't take non-existent pages and 301 them to the HOME page.
I think that what you are doing is PRETTY similar to that.
We have also checked that almost 90% of the major authority competitor sites in the exact same niche (I would say ranking within Alexa 500) are doing the same. i.e. doing a 301 redirect to the relevant category, just like its happening in this case. This has led us to confusion whether we should treat them as 404 or simple carry on with the 301 redirect as exists.
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.
We were thinking of doing something on similar line, but not sure whether we should do it or not because its a major step and we want to be totally sure before making this sort of massive change.