"Why are open source file sharing applications so popular? The
answer to that question may be obvious to some, but the explosion
in paid-for, online digital content services in recent years hasn't
dented the download rates of free file sharing applications.
"At the time of writing, open source software repository
SourceForge.net lists the top four downloads of all projects to be
related to file sharing. TechWorld takes a look at five open source
file sharing applications that can be used for good or evil..."