The prohibitive size of video files is just one barrier facing companies hoping to enter the sector.
For example, while a song in MP3 format can be downloaded in less than a minute on Napster on a high-speed network, a full-length movie would take hours to download on Scour Exchange, even with an network as fast as Harvard's. For users with lower network bandwidth, the download times are slower.
"In that video files are much larger than music, bandwidth will be a major constraint," says Centerspan's Halasy. "However, we do feel that eventually, video will be exchanged as audio is currently."
The software that converts DVD-quality movies into easily-transferrable files is also difficult to find. Under the Digital Media Copyright Act, it is illegal to distribute DeCSS, the program used to decrypt DVD movies and copy them onto disk. The MPAA has routinely threatened those who post the program on their websites or servers with legal action.
Still, there is speculation that Napster may ultimately allow video to be traded on its servers. Fanning, however, has said his company is currently focusing all of its development efforts on creating a fee structure, in alliance with record label Bertelsmann AG.
But when firms like Napster or Centerspan begin to charge for use of their file-swapping services, it is unclear whether the users will follow--especially with free, though potentially illegal, options still out there.
"Free peer-to-peer systems (e.g. Gnutella and Freenet) are multiplying and becoming more user-friendly," writes Fisher, who is also a member of the Berkman Center. "If a chastened Scour began charging for its services (as Napster/Bertlemann suggests it will), then many of its 7 million users would likely flee to free alternatives."