Encrypted Blogging

I envision having the ability to encrypt individual posts for consumption only by those that are pre-authorized to read. That way, it would be possible to maintain privacy while still having the capability to post in public places.
Possible applications:
– Very personal blogging (for friends, family)
– Online diaries for private consumption only
– Message areas (bulletin boards) for closed groups.
Possible components:
– GPG to manage keys
– a “per-post” key selector (embeds as many keys as needed in the post)
– editing of privileges after posting (adding/revoking) read rights.

Please let me know your thoughts. If you know of any efforts to develop this, I would greatly appreciate a pointer.

Thanks!