Stacker is a command line program that combines the data from one or many files into one big file. It is not an archiving program. It does not compress data. The file types intended for use with stacker should already be compressed. The initial drive behind stacker was to provide a somewhat anonymous, private way for file sharers to store and share their files. Information as to what files are in what stackers can be discreetly spread by word of mouth on file sharing forums and chat rooms.