This feature has been in the backlog for about a year now.  I'll see if I can't put something together on RRS in the next week.

I often manage notice board postings at events. They are often digital notice boards. 

1. Yachtscoring's notice board actually lives in the email to competitors dialogue box. You have to send an email, then check "post to notice board". After Louis passing, the company is still going. I hope they can succeed. 
2. In Clubspot, my work flow is to compose a notice, post it as a document or as free text in the notice board, then use the communications tools (actually in entry list) to copy/paste the notice to an SMS and/or Email to all competitors. These will include a link to the notice board even though the notice text is included. 
3. Most of my race docs state the link to the online notice board and that there will be a physical, unofficial notice board attempting to mirror the online notice board. 
4. If we have a club flag pole, I'll often fly flag L with a sound when a notice is posted physically to the unofficial notice board to draw attention. I carry Flag L in my judging kit for this purpose. 
5. Of course, we coordinate with RC on all of this and usually offer to post their notices so one person can cover "tech and paper" well for the event. 

All of this is imperfect and screaming for a better solution, but it practically works with someone "owning" it. 

Hi Mike

We often use WhatsApp* to notify sailors of signals ashore (ditto posting of notices on the ONB). The official signal is still made ashore in the usual way, but sailors are notified of it by WhatsApp so they don't need to be near the flagpole to 'see' the signal. Still has to be done manually though (by the race office putting the message on WhatsApp).

Graham
* Other instant messaging apps are available