Often developers have already begun work on a design while details are being finalized. I can send a manual note that they need to refresh the design specs to see new updates, but it would be nice for a private link to send an email to all shared addresses as soon as an update has been made to the link, or to anyone who might have commented on the link for a public link. This would facilitate keeping everyone as up to date as possible. Alternatively having some kind of notification show up on the actual designs specs page saying "Updates have been made to these design specs" would be very useful.