Valve has launched the Map Workshop for Counter-Strike: Global Offensive, making it easier for players to discover and play new maps and modes that come straight from the hands of the Counter-Strike community.
With the new Map Workshop, players can find new maps, vote for favorites and subscribe to maps and game modes as well. Upon subscribing, Steam will automatically download and update changed made by the author. Maps from the workshop can be used in quickmatches, private matches through Play With Friends, and offline bots as well.
You can learn all about the Map Workshop in more detail right here.