SubmitHub has a built-in chat system so you can talk to curators (and SubmitHub staff) without leaving the site. It's the default way most communication around an approval happens.
Where to find it
Click "Chat" in the top nav for the full chat page, or the chat icon in the top-right corner for a quick pop-out. Both show your conversations sorted by most-recent activity.
Private chats vs. chatrooms
Hiding chats yourself
Inbox getting cluttered? Use the archive button in the top-right of any open chat to tuck it out of your sidebar. It'll pop back into view automatically the next time the other person sends a message.
Auto-archive on quiet approval chats
This is a separate thing. If you got an approval from a curator and nobody's said anything for roughly 2 months, the message input on your side quietly disappears and an "Archived" notice takes its place.
It's intentional. The reason that chat existed in the first place was a specific approval. Once it's been handled and weeks have gone by, we don't want artists pinging the curator about something long since wrapped up.
The lock is one-way: