Do not fear, the original (and best) Aggregator sites are here to stay! Hat tip to reader Simon M. who gave me the tip of subscribing externally to the RSS feeds of the geeklist announcement threads. Have done so for now and will see how that goes for March. Thanks Simon!!!
Leaders are calculated based on unique entries each month. A unique entry is a single game (or one of its expansions) by a single user in a single month. This eliminates multiple entries for a game by the same user during a month (an acceptable practice, but one that dilutes the stats).