Abstract: A method of distributing electronic audio or video content from a distributing computer system to a user device (such as a computer, PDA or mobile telephone) over a telecommunications network, comprising: the distributing computer system detecting at least one characteristic of the user device, the distributing computer system selecting a version of the content according to the characteristic, and the distributing computer system transmitting to the user device the selected version of the content. The invention also provides a method of processing electronic content comprising: encoding the content with programming code indicative of playback preferences, for facilitating preloading of the content, for detecting at least one characteristic of a user device or a communications link thereto, or any combination of these. The programming code may be inserted automatically or manually, and may comprise a link.