Just noticed I'm not receiving any alerts for my watched threads although I have it set to display in my account settings here. Not sure if it's just me or anyone else has noticed this.
It's an alert for a thread that I haven't visited today (my resource thread, btw), and the reply that should have triggered an alert was posted just 30 minutes before I viewed it. These were working yesterday...see my screen grabs:You will only ever receive one alert for each thread since you last read it.
You may have not been around for a few days and the alert has expired, or you previously ignored an alert for that thread, so you won't get subsequent alerts until you visit the thread again.