Digital distribution (also referred to as content delivery, online distribution, or electronic software distribution (ESD), among others) is the delivery or distribution of digital media content such as audio, video, e-books, video games, and other software. The term is generally used to describe distribution over an online delivery medium, such as the Internet, thus bypassing physical distribution methods, such as paper, optical discs, and VHS videocassettes. The term online distribution is typically applied to freestanding products; downloadable add-ons for other products are more commonly known as downloadable content. With the advancement of network bandwidth capabilities, online distribution became prominent in the 21st century, with prominent platforms such as Amazon Video, and Netflix's streaming service starting in 2007. Content distributed online may be streamed or downloaded, and often consists of books, films and television programs, music, software, and video games. Streaming involves downloading and using content at a user's request, or "on-demand", rather than allowing a user to store it permanently. In contrast, fully downloading content to a hard drive or other form of storage media may allow offline access in the future. Specialist networks known as content delivery networks help distribute content over the Internet by ensuring both high availability and high performance. Alternative technologies for content delivery include peer-to-peer file sharing technologies. Alternatively, content delivery platforms create and syndicate content remotely, acting like hosted content management systems. Unrelated to the above, the term "Digital distribution" is also used in film distribution to describe distribution of content through physical digital media, in opposition to distribution by analog media such as photographic film and magnetic tape (see digital cinema).