FAQ / documentation material

Some questions that need good answers before Keybase opens for the general public.
1. ‘If a service is free, you are the product being sold.’
Why is that not applicable to Keybase?
2. Keybase is based in the US. Why is our data safe? Note that even though an uploaded private key is encrypted it is still vulnerable to attacks.
3. Is the Keybase server software open source, in other words, can I audit it, and run my own Keybase server?
4. When a user deletes his account, is all information physically removed? Will it be kept on archives and backups?

The issue contains four unanswered FAQ questions about Keybase's business model, data safety, server open source status, and account deletion. No file, test, or documentation entry point is named; start by locating the project's FAQ material and confirming the appropriate maintainers or source of truth for each answer. Done means providing approved, accurate answers for all four questions in the relevant documentation.

Written by the indexing model from the issue text.