Update status aggregator is two modules: a "client" and a "server". The client, update status notifier to be enabled on all sites that are to report to the central tracker, sends a list of installed modules and their status to the tracking site via xmlrpc when cron is run. This information is taken from the update status module. The server component, enabled on the tracking site, receives these lists from all the clients and creates nodes for each module. These nodes will then get updated every time the cron is run on the tracked sites. For the tracked sites to have the right to create these nodes, the keys of the tracked sites need to be entered into the tracker site.