These session will be promoted before and during the conference. There will be a slack channel dedicated to each session. At the conference, each session will have its own dedicated table, where attendees can meet-up and discuss the topic of their session. Sessions will also be promoted on the main conference screen and each table can optionally present a five minute 'Lightning talk' on the main stage at the end of the conference.
Ideas for sessions might be, for example, people interested in chat apps / people interested in nosql libraries.