Download
To download is to receive data from a remote or central system, such as a webserver, FTP server, mail server, or other similar systems. A download is any file that is offered for downloading or that has been downloaded. The word's primary usage comes in the form of a verb. Increasingly, websites that offer streaming media or media displayed in-browser, such as YouTube, and which place restrictions on the ability of users to save these materials to their computers after they have been received, say that downloading is not permitted. That is, "download" is used to mean "receive and save" instead of simply "receive".
Upload
The opposite operation, to upload, is to send data from a local system to a remote system, FTP server, or website. For example, "Uploading a video to YouTube" means sending a video to the website

Music Download
Legal music downloads typically involved the a purchase of a song or album available for downloading on the Internet. Downloading music first became popular with file sharing technologies such as peer-to-peer networks, with people breaking copyright laws by not paying for any of it. The Recording Industry Association of America (RIAA) claimed that this practice was damaging the music industry, and a series of law suits led to many of these networks being closed down. However, those who support such technologies argued that the music industry said the same thing about recordable tapes and CDs, and even when recorded music came out as before then artists got their money through live performance, and that the industry should embrace the advancements in technology rather than enforce prohibitions on the practice. Very little publishable academic research has been done to clarify this form of massive consumer behavior.

Video on Demand
Video on demand (VOD) systems allow users to select and watch video and clip content over a network as part of an interactive television system. VOD systems either "stream" content, allowing viewing in real time, or "download" it in which the program is brought in its entirety to a set-top box before viewing starts. The latter is more appropriately termed "store and forward". The majority of cable and telco based VOD systems use the streaming approach, whereby a user buys or selects a movie or television program and it begins to play on the television set almost instantaneously.
Often, nowadays, the term encompasses a broader spectrum of delivery devices, referring not only to set-top-boxes but also computers, mobile phones and indeed any system that can receive on-demand audio-visual content over a network.