Let's start with the easy thing: which questions to delete?

1. These

Because these questions bring in the traffic to this website.

2. Anything with zero or negative votes. These questions are usually extremely low quality with blurred photos etc.

3. Questions that have positive votes and more than one answer achieved that because they either had a nice pretty picture inside, or somehow ended up in the hot network questions. These should go to.

Which ones to retain? Things like What kind of rock is this being eaten by a rock-eating worm?. There are two reasons for it:

1. The title is specific enough to not attract internet searches for a generic "help me with my rock".
2. The question is not about a rock in one's possession, but about a rock discussed in the media. Therefore it has widespread interest, beyond the personal curiosity of the OP, hence the upvotes.

Other potential questions-to-retain can be judged on the basis of their own merit, as each one is unique and may has its own reasons to survive the cull.

However, a notice should be added to question to mark that the question is now considered as offtopic, but it is of exceptional interest and kept for historical reason.

Let's start with the easy thing: which questions to delete?

1. These

Because these questions bring in the traffic to this website.

2. Anything with zero or negative votes. These questions are usually extremely low quality with blurred photos etc.

3. Questions that have positive votes and more than one answer achieved that because they either had a nice pretty picture inside, or somehow ended up in the hot network questions. These should go as well.

Which ones to retain? Things like What kind of rock is this being eaten by a rock-eating worm?. There are two reasons for it:

1. The title is specific enough to not attract internet searches for a generic "help me with my rock".
2. The question is not about a rock in one's possession, but about a rock discussed in the media. Therefore it has widespread interest, beyond the personal curiosity of the OP, hence the upvotes.

Other potential questions-to-retain can be judged on the basis of their own merit, as each one is unique and may has its own reasons to survive the cull.

However, a notice should be added to question to mark that the question is now considered as offtopic, but it is of exceptional interest and kept for historical reason.