Multimedia is multi-disciplinary – most multimedia applications are a combination of a number of different skills such as digital design, programming, video/sound editing, networking, writing etc.
These are some examples of websites in which they are using multimedia.
Miniclip is a video game website in which they are using multimedia and you can play video games online.
Argos is using multimedia and pictures to advertise their products.
YouTube is using multimedia for Videos, Sound, pictures and etc.