kibitz allows two (or more) people to interact with one shell (or any text-oriented or character-graphic program). The people may be distributed across a network. An interesting display of what Expect how leverage can multiple interactive programs (a shell and multiple instances of telnet, ssh, etc).
Contrast kibitz with xkibitz which is a tool that lets multiple people interact with one xterm simultaneously.
Contrast kibitz with multixterm which is a tool that lets one person drive multiple xterms simultaneously.