I recently submitted some some feedback for a puzzle and the puzzle maintainer responded to my feedback. When they did this I got a blue notification with a read button. Cool, except that clicking on the read button brought me to the blank URL:
http://online-go.com/mail?id=34632
I assume this ID has something to do with the mail, or its old? Either way, I was able to access the message for real by clicking on mail in the menu (which also showed a notification by the word mail), which brought me to:
http://online-go.com/mail
From where I could view the message.