Jiglu's Radar is your personal home page in the system, bringing together all the information you need for your most common interactions with the system.
The main section of the page is taken up with your activity stream. This shows all the new contributions that have been added to the groups that you are a member of. You'll be able to view the contributions and respond to them. As soon as something new is published you'll be notified and can then update your stream to include the new contributions.
More information on the Radar is available in the help system.