E-mail notifications work for me. It seems the forums makes a "delayed notification" by default. I don't know how long of a delay it is, but it's not immediate, hence the "delayed" thing. You have to go into "My Controls", look in the left sidebar under the heading "Subscriptions" and click "View Topics". There you can manually change your posts to "instant e-mail notification" to get e-mailed as soon a a reply is posted.
You may also want to check your spam or bulk folder. Sometimes it will mistake GBAtemp EM's as spam and the EM's go in there.
If you STILL aren't getting your notifications.......erm.....maybe you didn't set the topic to notify you?
Hope that helps ya!