How am I notified of new messages
By default everyone receives notifications by email and can opt-in to receive push notifications or SMS notifications.
Recommended—Push Notifications with the iOS or Android Apps
Other—Email or SMS
You can toggle email or SMS notifications by going to the notification settings page.
When you have a new message, you'll see a little bubble next to the 'Messages' tab, with the unread count in it. This automatically updates, so you do not have to refresh the page manually to see how many unread messages you have if you are using a web browser.