GOG has added user profiles, continuing the DRM-free digital games store's cautious steps in introducing Steam-like social features. If you want to share your GOG gaming activity with the world, post pictures, compare achievements, and all that, you now can. If you don't want to share with the Internet, well, the privacy settings will let you turn off much--but not all--of it.
Similar to Steam, GOG's user profiles are accompanied by a Feed showing what your pals have been up to - what they've been playing, achievements they get, posts and pictures they put up, forum posts, and so on. You can customise your profile with backgrounds, write a little profile. And it shows the games you own, how much you've played them, the achievements you've got... you know, it's a profile.
If you don't want to share everything with the world, it does have let you lock bits down. Your profile page, full game library, and friends list can be set to visible by everyone, only your pals, or only you. It also has a visibility setting so randos can't find you.
The privacy settings are imperfect, mind. As some forum posters have pointed out, some social and play information is still visible even with everything supposedly locked down. And I do think that if a service doesn't have profiles from the start, when it does add them they should default to private.
Social stuff on GOG feels a little strange. The store stood apart from Steam by being stripped-down and DRM-free. Social stuff feels natural on Steam because the store and client grew in its early days because of Counter-Strike, while GOG was all about decades-old singleplayer DOS games. But ah, what the hey, it's relatively minor and I'm sure many will enjoy all this. If GOG fix the privacy issues, I'll happily disable and ignore profiles while leaving others to social their hearts out.