Seriously though, it could be your email server, or something in between. Our code doesn't loop 4 times and if we had a systemic issue like then chances are we would have seen it either in testing or real life, not to mention the hordes of angry people yelling at us.
If you can look at the meta data on the emails themselves you'll be able to check if they are the same (as in, the exact same) email, or if they are separate emails we've sent individually. That may help narrow down what's happening.
Seriously though, it could be your email server, or something in between.
No, because I got the notification 4 times near my name at the top right hand side of the page, too.
You know, this shiny white number on the red background (Which is always above 1000 on your account )...
I tend more to Matthews idea, what happens if the poster of an answer does edit the answer right after posting it?
I have seen the multiple notifications, but never multiple emails.
This is not as bad as another site I used to be on (I think they shut down), where each reply would give around 50-100 notifications/emails. I terminated my account there (as did most other members) after the site's development team said that was 'by design'. WTF?