Take your pick of any of the points & miles blogs that post regularly/daily - they all parrot the same breaking news and deals. You can watch like dominoes as the news pops up on one after another so as not to miss out. Just patronize the blogs that you feel provide you with value in general - there isn't really much they can add to the award discount announcement other than telling you it exists. Personally I find Doctor of Credit and Frequentmiler to be reliable.
You could also see if there are threads on FT for the programs that regularly have such promotions. If so, you can subscribe to the thread and have it set for email alerts when there are new posts. I'm not sure if anyone maintains an FT thread that covers all of the deals in one, though.