Publish certain information for Meteor.users and more information for Meteor.user

Right from Meteor documentation:

Meteor.publish("userData", function () {
    return Meteor.users.find({_id: this.userId},
        {fields: {'other': 1, 'things': 1}});
});

And also:

Meteor.publish("allUserData", function () {
    return Meteor.users.find({}, {fields: {'nested.things': 1}});
});

Hope this helps.