I would hope the shout-out system has some form of protection in place, again to me this would be some relationships table somewhere saying this post mentions this user and a boolean saying if a notification has been sent. Let's try Cedar War Cedar War. Well wasn't that interesting! It sent me two notifications, but updating the post even to the point of removing and re-adding the mentions in a different order did not trigger new notifications.
I think it is on the spreadsheet. It's on the list (again)... It's just one of those super low priority things that kept being put off. I think mk is actually on it now.
Oh it will be. The problem here is that you can force Hubski into sending too many emails, this may exhaust any mail allocation that the server has but more likely will get Hubski blacklisted as spam -- blocking new users from signing up as they can't verify their accounts etc and incurring financial expenses to mk as he'll have a rough time getting un-blacklisted.