I think that it would be far more advantageous to convert Diners Club Reward points directly to airlines, rather than transfer the club reward points to Starwood and then to airline miles.

My original question still stands. How does Starwood keep track of where your points came from (or do they)? I don't keep track of the breakdown, though in my case most of them come from either stays or Sheraton Optima card, and the occasional car rental bonus. I can imagine that in a few years, it will be quite hard for me to account myself the exact breakdown of my points.