According to http://meta.stackexchange.com/a/92006/141361, we automatically delete old question with negative/0/1 scores (depending on time passed) and no answers.
I'd like to suggest extending something like that to closed questions as well.
In general, closed questions with no good answers are bad for the Internet, because they represent a dead-end page; a page with a question and no good answers, and it can never receive any other answers as well. If anyone ever Googles for that, all they get is a useless page. A useless page with our branding.
I propose to automatically delete these questions, to make the Internet a better place. My proposed criteria:
If a question is more than
30days old, and ...
- It is closed (except if it's closed as duplicate)
- It has no answers (or if we feel more strict: it has no answers with score 0 or more)
... it will be automatically deleted.
The big difference from the policies linked in the other post is that now the question score doesn't matter - the reasoning is that, again, if it's closed and unanswered it's a Bad Thing, no matter how it is scored.
Notice - I don't just propose it to deal with a theoretical problem, I have noticed quite a few closed questions get upvotes (e.g. "cool" questions that are closed because they are prohibited by site policies). If would be great if those won't require manual cleanup later.
EDIT: according to the data found by Conrad and posted below, we might have thousands of these dead-end questions with over a million views between them, on SO alone.