Well, i was thinking why not have a chatroom with this gallery, i think it would be useful. Be able to chat to your guest and reg user's... (family,friends,Customers) depending on how you use the gallery...i mean theres a mod out there so you can see whos currently on-line on the gallery why not being able to chat with them...
Just a thought....
Not suitable to be a core feature, a shoutbox could probably be made as a plugin.