301 or 404?

[PanuKuuluvainen]

My client has a classified ads website with hundreds of thousands of classified ads. These ads expire quite fast. When the ad expires it gets removed. At the moment this results in a 404 page and thus hundreds of thousands of 404 erros in Webmasters Tools.

From what I know this damages SERP results due to slow indexing of important sites and 404 being just plain bad SEO.

I suggested doing a 301 from the expired ads to a upper category but this feels like cheating. The content hasn't actually moved, it has been removed.

What would you suggest?

[SEMPassion]

I would not want to be generating all those 404 errors.  My recommendation would be to 301 them to the top of the category and dynamically provide a error message that the classified they are looking for has expired, but here are lots of other ads in that category that might help them find what they are looking for.

You want to provide a good user experience and this would certainly be better for the user than simply a page not found error message.

[mlentner]

I would agree with Chris. Having the generic 404 appear is not very helpful for the user. Linking them over to the same category with a 301 would be better from the Search Engine perspective and the usability perspective.

[Everett]

When you're dealing with hundreds of thousands of 301 redirects you're going to probably notice some serverside performance issues. It is certainly an option, and if you don't see the site slowing down I'd use Chris's recommendation, including the messaging if possible.

But if you notice the site slows down significantly you could just leave the page up but dynamically add a follow,noindex meta tag in the header area, and show the message suggested by Chris on the original page instead of the old add. The message, of course, would link to the appropriate category to help them find what they're looking for. Users will no longer be able to get to that page from the search results, and I assume you'll keep those pages from showing up in internal search results too. The only way anyone would get to them would be a direct link, bookmark or some similar direct method.

This method would allow you to keep from having to do so many redirects, and would provide a good user experience. It would also solve the problem of having all of that old, thin content in Google's index and risking a lot of back-clicks or "block this site" clicks, which could bring on the wrath of Panda.

If you find that your old ads DO have a lot of links going into them it may be worth redirecting them so your category pages benefit from those links. Or you could use a combination. For instance, use my suggestion for most of them, but if you find some that have lots of external links you could redirect those on a one-by-one basis.

[PanuKuuluvainen]

Thank you for your quality comments. I think we are going to go for Evaretts suggestion since I do feel like hundreds of thousands of 301's might be a bad idea.

We are also discussing the possibility of keeping the old pages (do index, do follow) up with the old ads, just removing the seller information. We believe that users might well be interested in information about past items sold or expired. This wouldn't require any 301's, just dynamically adding the message suggested by Chris and a search engine/index to help find interesting sold/expired items.

This way we could generate hundreds of thousands of content pages which might over time bring plenty of quality traffic to the website. These pages would have dynamically generated fresh content (new suggestions about relevant ads) so I don't feel too worried about old content in Googles index. We could also consider scraping some details of the sold item from the manufacturer website.

I've never dealt with this many pages combined with this thin content before so The wrath of the Pand worries me a bit. However the root domain is quite strong and these ads seem to draw quite a few links.

The question that requires some further thought is whether or not having this many old, thin pages in Google's index will prove problematic. Thoughts?

ps. Since I didn't mention this before, the website is about used cars