This is discussion archived from a time before the current discussion method was installed.
:Sorcery and Cecilia doesn't count. It only had two authors.
: But they took turns writing their own sections, chronologically, and with no previously agreed plot outline. Even if there is disagreement on whether a story with only two authors can count as a real round robin, given how few round robin stories are professionally published, I think it is worth keeping as an example, although perhaps with a note indicating that it had only two authors.