I am building https://bugshare.io to be community focused product with additional features you can pay for. I was wondering if it was a good idea to allow users to have unique usernames for their profiles, or just use their user id and a slug of their display name.    https://website.com/@julian  or  https://website.com/users/1337/julian    A real world example would be, the stackoverflow style for user profiles  https://stackoverflow.com/users/10548884/coder-guy    and    the makerlog style  https://getmakerlog.com/@_UchennaOkafor    I would also love to hear which one you prefer and your reasons why.