Niconico offers a schedule of user and corporate-created content and carries a monthly subscription fee of about $5. Comments from Niconico livestream chats typically scroll across the presentation itself, but the overlay can be turned off. It's unclear if Niconico will require a PlayStation Plus membership for broadcasting on PS4, but for reference, Twitch.tv can be used without a PS+ subscription.
Nintendo purchased stock in Niconico last November, noting a request from the Niconico chairman Nobuo Kawakami to do so.
[Image: Niconico's Facebook]