I was subscribed to this but signed off for my current round of SYC. Basically you sign up for notifications of when your favorite brands go on sale and how often you want to receive those notifications.
I was signed up for DVF and Theory and a few other brands... there were some really great deals and it was better than having to sift through all the department and online stores webpages to find individual sales.
It's not a bad idea if you are drawn to high end stuff that rarely goes on sale - they just email you if it ever does.