I suspect that there might be a system bug in the Noticeboard. A colleague recently published a notice on 17 August. That should have generated an email notification to all those who have signed up to receive them. But I didn't receive an email notification, neither has another colleague which is suspicious. If I'm correct it means that no one will have received an email notification relating to this notice.
The person who wrote the article is currently away so it is not possible to confirm, but I suspect that before being published it may have been saved as a "draft" (it is quite long and information may have been added piecemeal as and when it became available). I experienced something similar a couple of years ago when I saved an item as a draft and no corresponding email notification was received. Since then have not saved anything as a draft on the Noticeboard (preferring to publish and I have had no problems).
I suspect that for some reason when a notice is saved as a draft, an email notification is not sent out when the status is changed to publish (like when a correction to a notice is made).
As a Blog entry works in a similar way to a Notice will there be a similar issue?
I've tested this out and can't reproduce the problem - the notification is sent whenever the noticeboard or weblog entry is published, whether saved as a draft first or not.
Also if I unpublish then republish an entry then the notification is sent again.
It's too far in the past to have a record in the database of whether the notification was sent - but if you want to be sure that it's working then next time you publish something drop an email to email@example.com and I'll check if something was sent.