A few times now, I've been seeing flags of high-reputation users deleting valuable content.
The specific reason I'm doing it is because all users have:
You agree that any and all content, including without limitation any and all text, graphics, logos, tools, photographs, images, illustrations, software or source code, audio and video, animations, and product feedback (collectively, "Content") that you provide to the public Network (collectively, "Subscriber Content"), is perpetually and irrevocably licensed to Stack Overflow on a worldwide, royalty-free, non-exclusive basis pursuant to Creative Commons licensing terms (CC-BY-SA)
This means that you cannot revoke permission for Stack Overflow to publish, distribute, store and use such content and to allow others to have derivative rights to publish, distribute, store and use such content.
Posting just so that it's clear. Feedback appreciated, but I'm not sure what we should be doing differently.