I think it would be so cool to have a game where you have user made maps, game saves, friends lists and all that sort of stuff without needing to worry about logins and that complicated sort of stuff.
Yes. But for this, Itch needs a major overhaul. Maybe starting with friends lists and direct messages and such. Oh, and direct messages won't be coming any time soon, because they are a moderation nightmare. They would need some concepts that are low maintenance. User interactions of any sort are not low maintenance as a rule. If it were easy, such features would be seen on Itch since long ago. This thread is 5 years old. And was recently bumped. I just wanted to add my todays perspective: it is a bad idea.
And leafo already said, if such a feature would be done, it would be opt in. And it would have to be per developer. Quite a lot of permission data. But asking users to share their information with (amateur and unknown) devs is a bit wobbly. Who would guarantee that no illicit things are tried with the data? And Itch is constantly under attack. There are hacked accounts every day. Most are from discord hacks or downloaded fake games. But if there are ways of attack that can utilize browser games, scammers will use this in some way. If they are successfull often is another story, but they will use and try to abuse the system. Browser games are "safe" because they run in a sandbox in the browser. Any kind of unneccesary exposure is a risk. Also, some people would be very concerned about privacy. Just because you probably won't be hacked, does not mean you would want to see your name somehwere. Opt in is nice on paper, but it does not work as a concept. There are just too many things the average user does not grasp, what such an opt in would entail.
The reason there are no examples is that the feature isn’t fully implemented. Most traffic doesn’t use the itch.io app for web games, so it would prevent most users from using the feature.
If the needed api would require the usage of the Itch app, all this is moot wishfull thinking anway. And the api that already is there is not used? I mean, not web games specifically, but no games at all? (That you know of). Too exotic a use case for the mostly drm free games maybe. I have seen drm games, but very, very few. I could not name it, actually, I just dimly remember seeing games that had some kind of launcher or login data or whatever.