Possible types of session you could run include:
Group video discussion.
Pre-recorded video from someone with domain knowledge, played back to a group with a simultaneous discussion.
Timed, live Twitter discussion.
Slack chat, exported afterwards.
Group phone call.
Live editing of a Google Doc or similar.
Group podcast.
Whatsapp chat.
Group watching of a pre-existing video, with simultaneous chat.
You can run your sessions any way you like. We've made a list of possible platforms here but use whatever works for you and your participants. Please make sure that whatever you use you record video, audio, take notes or at least write a blog post (or tweet summary). We want to be able to share what you've done:
Google Docs
Trello
Zoom
Whereby
Jitsi Meet
Discord
Whatsapp Video
Miro
Mural
Stormboard
Youtube
Google Sites
Github Pages
Wordpress.com
Mailchimp (ongoing emails plus landing page)
Minecraft
Fortnite