From the sounds of it, all this site will tell you about is publicly available deals. You can sign up for the same type of alerts - at no cost - with your favorite airlines and/or a number of online travel sites. I would pass. Still, if you want to spend $20 per month, go ahead.
A caution note: If it's such a great idea, wouldn't you think there would be more Internet presence and a bunch of travel writers extolling the virtues of this offer, with all of that praise showing up in a Google or Yahoo search for this company? The fact that such glowing praise doesn't seem to exist is a clear warning signal to me.