The Zoom@CERN service has a limited number of webinar licenses that can be assigned to users who need them.
The webinar format gives organisers a stronger control over what the audience can do, so it limits the risk of a disruption by some participants, but the drawback is that the management of the event becomes more cumbersome as the hosts need to enable each user to talk when they need. Also participants cannot see other participants which makes the event less community-oriented and may look more artificial and impersonal. Only a limited number of use cases fit the webinar format: mostly public presentations involving people who may not be well acquainted with videoconference rules. Please check more information about webinars on the Zoom dedicated pages
The limited webinar licenses are currently assigned by the service managers manually, so please open a ticket with firstname.lastname@example.org if you need to use webinars. [Coming soon! We hope to soon provide a mechanism to share the webinar licenses through Indico].