Is the little envelope/message indicator in the top menu bar meant to flash all the time?

I thought it was only supposed to flash when you had an unread message, but it's been blinking at me non-stop since I created this account.

Any suggestions?

"HUMANS NEED FANTASY TO BE HUMAN. TO BE THE PLACE WHERE THE FALLING ANGEL MEETS THE RISING APE." -Terry Pratchett, Hogfather