This grand new feature sends an entire levels data (images, sounds, and script) to all of the clients for usage when needed. Such a feature allows the host, who is determined by players' choice, to play his entire custom level without having to manually copy such level over to the clients computers. Since anyone can be the host, the clients can choose who's level to play and make that person the host so that the level data can be sent to everyone. Don't worry about this level data overwriting your own levels. Only the currently accessed Host level data is stored in a folder called "ClientData" instead of placing the data inside of the "levels" folder where you store your own personal levels.