Activate allows messages to be sent to individual or multiple roles, particular work areas, to individuals or to everyone on the event. You can find your messages by clicking on the envelope icon when in an event. This will take you to your 'inbox' where you can see the conversation. 

Creating messages can be done on the same page. Click on 'Add Message' to compose and send your message. Ability to filter who sees your message using the filter options below.