To deplatform someone is to remove their access to a channel for delivering messages to an audience. Deplatforming may involve not just banning the user or discontinuing service but also removing any existing content the user previously created on the site or service.
The term is usually used in reference to social media platforms, such as Facebook and Twitter, where site owners have banned users whose communications have been deemed unacceptable for some reason. Deplatforming can also refer to removing users from other types of services. Cloud providers and ISPs, for example, may be said to be deplatforming someone when they remove a user to prevent them from disseminating a particular type of content, such as hate speech.
Deplatforming may also refer to a more global approach in which the user is removed from multiple large platforms. In early August 2018, Facebook, Apple, Spotify and YouTube all removed Alex Jones, creator of Infowars, a right-wing political website. Twitter followed suit a few weeks later.
Potential reasons for removing a user from a given service may be specified in terms of service (ToS) so that the provider cannot be accused of denying any offending user’s right to free speech. However, the effectiveness of deplatforming a user is questionable. Many people who had never heard of Alex Jones, for example, are likely to hear about him being deplatformed, become curious and seek out his content, bringing him a potentially wider audience than he previously enjoyed.