Enjoy fast-paced multiplayer gaming with Deathmatch Classic (a.k.a. DMC). Valve's tribute to the work of id software, DMC invites players to grab their rocket launchers and put their reflexes to the test in a collection of futuristic settings.
Most popular community and official game content for the past week.  (?)
What does popular mean?
It means the content you're seeing has been rated up more than it has been rated down for the given time period.