I constantly see users online and eventually can play with them (for an open game without password). But i feel a bit weird as we cant make friendship straight from the game.. apparently. How do u guys deal with that? Are the servers from steam the same of GOG? I know the pirated version of the game doesnt connect with these same servers...already confirmed.

You see the same game as the steam users online.
So yes, they are the same Servers :)