There are seven visual variables: orientation, colour, texture, value, form, position and size.
Although Wikileaks is a virtual collection of data, yet it is a good example of data visualization. It consists of main raw logs and files. It requires the reader to interpret the content. In addition, the data is not actively collected from Wikileaks, it is provided via anonymous source. The information still need formal journalist to dispatch the news.
Refer to an example of archive, Spotify, a streaming music share software, is a success. Unlike iTunes where users need to purchase and download the music in order to listen, Spotify offers live streaming for users to listen. This can settle some legal issue. More, users can purchase the piece of music if they like.