Since the release of the new Source engine included with the Orange box for Team Fortress 2 beta, a lot of people love the integrated Steam profile statistics. We just got confirmation from Valve that this is going to be implemented for all older Source games aswell.
Some changes are going to happen soon that will both upgrade the older Source games to the newer engine aswell as giving them the interesting player statistics per Steam profile just like the beta of Team Fortress 2. Apart from the upcoming addition of Multi-core CPU support, we think this is another great update to come for CS:S and DOD:S aswell as HL2DM.
More info will be posted as soon as we get it from Valve.