iirc it's something you just sign up for and rockstar will email you updates about the game and others. I think thats what it is i haven't played RDR in a long while. I think you unlock an outfit for that too? I know you can do it in game tho.
Ya if i remember correctly, you get a suit that either allows you to a) cheat at poker or b) play high stakes poker, i forgot cause one suit does A and another does B and i always got them confused
they give you challenges to complete and what not if you complete them you get rewards when the game first came out one of the rewards was the cheat to flaming bullets