I have a wordpress hosted blog where I must approve comments.
Initially it was set up to have emails go to an aol account. But aol is driving me nuts at the moment, so I changed the email on the blog account to a yahoo account. That was working fine for a while, but I was getting copies of comment notification both at aol and yahoo.
Today I stopped getting the notifications in my yahoo inbox. I checked earlier today and the email in my account was changed back to aol. OK. A little searching of the faqs and I found that you can't have two wordpress accounts on the same email (I also have a private one that I signed up for using my yahoo account). So I changed my email over to my gmail account (sigh.... I do have too many email accounts).
So now I'm getting the comment notifications in my gmail account (cool) but they are also slowly trickling into my yahoo account (I got notifications for two of the last three comments posted). Those three notifications came to gmail in all one batch but the two that came to my yahoo account came separated by about 30 minutes and a good 30 minutes after I had gotten the notifications in my gmail account.
On a positive note, it doesn't appear that I've gotten any notifications in my aol account.
Let me know if you need any other details.