Posted April 17, 2016
tinyE: One of these days someone is going to have to explain DRM-free Multiplayer. :P
It sounds like "water-free swimming".
It's quite simple actually. DRM stands for Digital Rights Management, meaning that it is functionality to prevent unauthorized users from playing a game. While multiplayer inherently requires a network connection, this is not DRM in and of itself. Usually however, multiplayer servers also check the validity of the clients' serial keys, which is where the DRM comes in. DRM-free multiplayer then, is a system in which the multiplayer servers do not authorize or validate the clients in any way (other than presumably checking the game version for compatibility purposes). It sounds like "water-free swimming".
Given that GOG permits the installation of its games to as many machines as you own, you can implicitly have several people in your household playing the same game at the same time with only a single purchase from GOG. With DRM-free multiplayer, those same people could be playing the game online against each other (legally mind you, given GOG's terms), which would be impossible with DRM'ed multiplayer.