The vault is still being added to. Not on a schedule and never quickly: closer to one question a week, when there is one ready.
The feed is how to hear about them, and it asks nothing of you: no address, no account, nothing kept about who is reading. A feed reader watches the feed and shows you what is new. Most readers will find it from the address of any page here.
A version that arrives by email is being prepared, for people who would rather hear about it that way. It is not ready, and there is nothing to sign up to here until it is.