I get notifications just fine! I think! I just don't get email for one of my primary give-out addresses! It doesn't go to my spam folder, it just evaporates! And Comcast doesn't seem to have any kind of IP-level whitelist tool!
(Thanks to aurora_novarum for reporting this and providing troubleshooting evidence.)
Anyway: I'm going to turn off my email link for now, because I don't have time to deal and don't want to break notifications. My alum (redirect) account apparently gets through to Comcast fine, and my work account is fine, for those who already know those addresses; if anyone needs to reach me by email, comment here and I'll supply a working email address privately. Comments will be screened for my safety as well as that of anyone asking me to email them directly.