Collaborate is the name given to the centrally supported ‘online meeting’ service.
Collaborate sessions can be managed entirely via a web browser with no need for client downloads. They can be scheduled via MyEd (useful for support staff and anyone who isn’t attached to a Learn course) or via Learn or Moodle (useful for course organisers / tutors wanting to host an online session with their students).
When scheduling the session, you can select to record the session for others to access after the event. You can also enable downloading of the recording to give you greater flexibility as to where to host the recording (you may want to upload to Media Hopper Replay for example).