The Command Center gives you an overview on several key elements of your ecosystem:
This is a list of current active events and which Microsite they are listed. It shows the current number of registrations for each of the events listed.
This is a list of your current Microsites/Engagement Hubs that have been set up.
This is a list of your current Email Campaigns - both Broadcast and Autoresponse Campaigns, and the number of contacts that are in the distribution list.
This shows new contacts that have been added through the Referral Campaigns that are active.
This shows the status of your contact database - the number of Active Groups and Contacts, and contacts added in the last 7 days.