File sharing is a multipurpose computer service feature that evolved from removable media via network protocols, such as File Transfer Protocol (FTP). Beginning in the 1990s, many remote file-sharing mechanisms were introduced, including FTP, hotline and Internet relay chat (IRC).

Operating systems also provide file-sharing methods, such as network file sharing (NFS). Most file-sharing tasks use two basic sets of network criteria, as follows:

• Peer-to-Peer (P2P) File Sharing: This is the most popular, but controversial, method of file sharing because of the use of peer-to-peer software. Network computer users locate shared data with third-party software. P2P file sharing allows users to directly access, download and edit files. Some third-party software facilitates P2P sharing by collecting and segmenting large files into smaller pieces.
  
• File Hosting Services: This P2P file-sharing alternative provides a broad selection of popular online material. These services are quite often used with Internet collaboration methods, including email, blogs, forums, or other mediums, where direct download links from the file hosting services can be included. These service websites usually host files to enable users to download them.

Once users download or make use of a file using a file-sharing network, their computer also becomes a part of that network, allowing other users to download files from the user's computer. File sharing is generally illegal, with the exception of sharing material that is not copyrighted or proprietary. Another issue with file-sharing applications is the problem of spyware or adware, as some file-sharing websites have placed spyware programs in their websites. These spyware programs are often installed on users' computers without their consent and awareness.