Notify all users of this new post?

[flynnibus]

I'm trying to setup a notification mechanism where I can get a notification out to ALL users (without having them manually subscribe to a forum) to notify them of an important post.

Using the generate email list from the admin CP isn't an option.

Ideally I'd like to have a flag on a post, that would instantly send a 'new thread' notice if selected for this post. But that sounds like hack area.. as I'd like to have it in the postbit as a checkbox or something.

Maybe more accessible I can think of is to setup a forum to post the notice in, which all members are subscribed to.. but have that subscription be automatic.

any ideas?