Not sure if this will help anyone with this problem but recently I installed a WP setup for a friend on her GoDaddy account and as my email address was used in the install, I suddenly started getting email notifications from her blog. I had done the original theme design on my ISP and when I went back to check if I could get notification from it, no go. So, I contacted my ISP and they fixed the problem right away.
It had something to do with a sendmail counter on their server having reached its limit. They reset the counter and increased the level and now I’m getting email from my WP blog. Version 2.0.4
Hope that helps someone. It sure is nice getting email from my blog again.