For some time now I have had a problem with receiving notifications from these forums. Every now and then I don't receive one and only find out when I browse the recent posts. At first I blamed this site ofcourse (as any selfish sod would), then I thought it might be GMail. So, I changed my profile to send notifications to a Bluebottle account but I was still missing the odd notification. Recently, I changed to a Yahoo account and for the period tested did not miss any notifications. I have since reverted to GMail and again within a couple of days have missed a notification. I suspect that both GMail's and Bluebottle's mail servers are filtering out what they think is spam before the mail gets to my accounts. Why they selectively pick those particular notifications is a mystery.
Anyway, I would be interested to hear of your experiences, if any.