What is the best way to handle deleted pages? Should I 404 the page?
For example, in a classified site, ads are added and expired every day. What should we do with ads that are no longer accessible? Is it OK to 404 the page?
We do it this way, but Webmaster Tools report these pages as 404 errors, and on a busy site, this number is always growing. Obviously, these pages were linked from other pages on the site, and google is reporting these pages, but when I check the pages that are present on WMT, these pages do not link anymore to the 404 page. What is also funny, is that if I check the google cache of the pages that are reported in WMT, the 404 link is not there as well...
Closely related question: How long do the pages typically stay up? You'd definitely want to flag them all as no-cache-- but do they stay around long enough to be worth indexing at all? Do they auto-expire after some preset time, or do they get taken down manually?