Counter-Strike: Global Offensive Trusted Mode Fights Cheating

A post on the Counter-Strike blog explains Valve continues its offensive against cheating in Counter-Strike: Global Offensive with the launch of Trusted Mode, which will prevent third-party apps from interacting with the multiplayer shooter:
Today we’re shipping changes to CS:GO that are part of our continuing fight against cheating.

CS:GO now significantly restricts the types of programs and files that can interact with the game.

By default, players will launch CS:GO in Trusted mode, which will block third-party files from interacting with the game.

If you would like to play while using third party software that interacts with CS:GO, launch with the -untrusted launch option. Note that in this case your Trust score may be negatively affected.