37-year-old Michael Nugent is facing charges of sharing extremist content including a manifesto published by the Christchurch mosque attacker.
He appeared at Westminster Magistrates' Court charged with 12 offences.
Mr Nugent is also accused of posting a video of the Christchurch terror attack on its one-year anniversary in March.
He's been remanded in custody by deputy chief magistrate Tan Ikram until 2 October, when he will appear before the Old Bailey.