No outside comms is a dogmatic belief of the QAnon cult. Of all Q dogma, it is one of the most important. Put simply, it states that QAnon will never post outside of 8kun, and all who claim to be Q on other websites are pretenders.
It was articulated in its current incarnation in drop 513:
IMPORTANT:
NO private comms past/present/future.
NO comms made outside of this platform.
Any claims that contradict the above should be considered FAKE NEWS and disregarded immediately.
WHERE WE GO ONE, WE GO ALL.
PATRIOTS.
Q
This has many practical effects, the most important of which is that Jim Watkins is entirely in control of QAnon. See also tripcodes.