About the "Summary of projects"
What's an active user ? active host ? active team ?
Of course they are active but how ?
Active is defined on this site as having a RAC of 1.0 or higher at the time the stats are calculated (at import time, all RAC values are recalculated to the same time point using the RAC decay formula used by the projects).
So, if you stop crunching for an extended period of time, your RAC will drop below 1 and you will not be considered active. Its the same for users, hosts and teams.