I've added user profiles. They existed before but were rudimentary, now they're a bit more fleshed out. Here's mine (link).
There are two types of profiles: Community Profiles gives an overview of the user across the website, and Game Profiles gives an overview of the user for a specific game.
With game profiles, you can also mark the status of a game (playing, completed, etc.) and keep track of your progress as you mark pages such as locations and missions as complete.
I actually released this feature almost month ago but forget to mention it since Breath of the Wild came out!