It's just Scott's Cheap Flights with a rebrand? It wasn't that great ~10 years ago.. Back in those days I used airfare watch dog pretty often.
It doesn't really matter where you get fare notifications.. You just need to watch the prices often enough to know what a normal price is so you can recognize a good price when it comes around.
Way back when I was finding round trip flights from NYC to Tokyo, Hanoi, etc.. I wouldn't pay more than $400 round trip. These days I'm only travelling to see friends or family so I don't track it as closely.