While I roll my eyes at The Mission Statement, Quora has stated two rationales for its walled garden which guarantee that the Internet Archive will stay on their spider block list:
- Authors retain copyright for their contributions, and Quora only retains a non-exclusive license to publish. The terms & conditions do not authorise blanket republication elsewhere without the author’s permission, and Quora would consider spidering to be republication. It’s why Quora is so restrictive on author’s self-archiving: you can only archive your own posts, and you can’t include others’ comments.
- Quora wants people to be able to unperson themselves from Quora—to delete their accounts and contributions to Quora, without them being retrievable elsewhere.