After watching this dramatic trailer for GOG.com's newly announced, optional Galaxy online gaming platform, I'm still unsure about how it will work in practice but, on paper, it sounds okay.
The new client, releasing later this year, will offer online multiplayer, game updating, social connectivity, and cross-platform play with Steam (and more platforms to come). According to GOG.com, none of this will be forced on anyone -- you'll never have to be online to play your single-player games -- and users can use only the features they want. Or none of them.
Sign-ups are open for Galaxy. By providing an email address, you will have a chance to take part in the closed multiplayer beta for The Witcher Adventure Game.