Never let it be said that fan support does not matter. Microsoft has apparently decided to do an about face after Halo fan backlash was so huge; they have decided they will not move forward with their plan to shut down the official www.halowars.com web site and the stat-tracking that takes place there.
This change of heart means that the site as well as the leaderboards and stat tracking will continue to be available for the foreseeable future. Fans could not be happier with the decision, and the Halo community does apparently agree that this is the right decision.
While the Halo Wars site could be moved at some point in the future, the company does still plan to integrate a lot of the actual content into the Halo Waypoint. The Halo Wars forums will still be moved to the Halo Waypoint forums. (Halo Waypoint is the official portal for all things Halo.)
It is possible that the location of the leaderboards and stats for Halo Wars might be changed in the future, but Microsoft assures us that they will get the word out, should a location change take place.