@scott sure but that's all-or-nothing and not granular. i want to be able to (for example) selectively say "i wrote this post" without revealing anything else about the post, not even the content or timestamp or audience. revealing anything more would be leaking more information than was requested.

or more generally i want to be able to share my email address with certain people but only upon request. an access control list works across an entire document usually, not across individual triples.