We've been considering doing that at hitlistapp.com. For now, we just send you alerts when we find deals that we've determined are good (or great or spectacular

We've been considering doing that at hitlistapp.com. For now, we just send you alerts when we find deals that we've determined are good (or great or spectacular), based on a proprietary algorithm for determining good deals that takes into account time to booking, price fluctuations throughout the year, and how desirable the destination is for you. We're different from Kayak or Yapta alerts in that you don't have to set alerts for a specific destination/time - you can search for things for, say, '7-10 day trips to South America between January 4th and 30th' or 'a long weekend in Austin in the next quarter'.