During the CD PROJEKT RED and GOG.com Summer Conference, the online retailer announceda new anti-DRM policy that will allow costumers to play their games without requiring an internet connection.
If you do want to connect to the net, GOG Galaxy is designed to be platform-agnostic; currently GOG.com and Steam players will be able to play together, but more platforms are also expected to be added in the future.
An optional client will be introduced later this year, and GOG say they've "already begun working with developers to implement the technology in their games."
The first title to use the tech is The Witcher Adventure Game, a digital board game from developer CD Projekt Red. You can watch the teaser trailer below, and visiting the allows you to sign up for a multiplayer closed beta.
You can check out the full GOG Summer Conference.