DLNA is a common standard that helps devices (mobiles, TV, PC, Xbox, PS3, camera, media players, NAS, etc...) to share digital media. For example device one (your phone) want's to share its media (picture, music, video) with the device 2 (your TV). If they are both DNLA certified and connected to the same network, then you can start displaying the media content from your phone to your TV.