Until about a week ago I was getting daily email from stackexchange.com (for every day on which I had any activity) notifying me of comments, answers to my questions, and chat pings across the network. I haven't received any of these notices for since June 9, though I continue to see the corresponding activity on profile pages and in the global notifications area in the top left corner of every page. These messages haven't started going to my spam trap; it appears that they aren't arriving. Why might that be?
I think I see what's happening now. It appears that when the new notification system rolled out (the red circle in the top left corner), the email system also changed: it only appears to send out notifications that are new as of the time the email is sent. (With the old system I got everything via email, even if I'd already seen it.) Since, with the new notification system, I see and clear notifications promptly, there usually isn't anything to email. But I have gotten email at times when I've been offline for a day or two and received notifications during that time. So my conclusion is that the email notifications haven't stopped, but they now only send new notices.