Hasn’t happened to me yet, but it’s notable. (Thx Andreas.)
this happened to me for the first time today. gmail just refused to load in my browser. it claimed to be loading, and then came up with a message that something was wrong with google’s servers and to try again in a few minutes. I did that for a while, then tried it in IE, and it worked fine. so I went back to firefox — nothing. deleted the mail.google.com cookies and restarted firefox. all’s well.
fyi if it ever strikes you.