Rabb.it is a website in which you can control a Rabbitcast (a virtual machine limited to Firefox) to surf the web and watch videos and movies, as well as voice/video chat, chat through text, and do many other things. OT started parties on the website around early 2016 when an OT'er discovered the website. Rabb.it is considered an offsite link on the forums, so many people who host parties get moderated for it.
How it worksIn a Rabb.it room, the host starts up a Rabbitcast and then invites other OT'ers to said room. From then, one user (whoever claims the remote first) can do whatever they want on the web by controlling the Rabbitcast. When the controller is done using the Rabbitcast, they can drop the remote. Additionally, the owner of the room can steal the remote back at any time.
Rabbit is known for acting as an easy workaround for users IP banned on ROBLOX or other sites, as it acts as a simple and accessible VPN, overriding all IP's. However, it is not recommended to use the site for illegal activity, as the IP's users can be tracked by the site.
Generally, OT'ers most commonly use Rabb.it to watch movies, chat with eachother, listen to music, or play flash games. However, some edgy OT'ers will use it to 'force' people to watch porn or gore (with some going so far as to use the site to access .onion sites). Because of this, the owner should be careful about who is able to get the remote.