Abstract: A ball joint unit movable along guide grooves according to an embodiment of the present disclosure includes: a first member formed in a spherical shape, having axial lower end fixed to a fixed object, and having a first guide groove and a second guide groove perpendicularly crossing each other along longest circumferences thereof; and a second member extends downward at four sides to receive the first member therein, having four sides movably disposed on the first guide groove and the second guide groove, and supporting a moving object thereon.

Abstract: A display apparatus includes a controller configured to control reproduction of content, a communication circuitry configured to request a server for broadcast channel information related to content being reproduced, and a display configured to display broadcast content related to the content being reproduced, based on the broadcast channel information received from the server.

Abstract: Provided herein is a display apparatus, a method thereof, a server, a method thereof, and a system including the display apparatus and the server. The display apparatus includes: a display configured to display a screen; and a processor configured to output for display, on the screen, a virtual channel list that includes at least one channel to which web-based service information is mapped, and to output for display, on the screen, a web content obtainable through a web-based service of the at least one channel of the virtual channel list according to a predetermined event.