Every Wikimedia hackathon ends up having their own organization mailing list, and every time a new event starts basically from scratch, discussing most of the times about very similar topics. What if we would have just one mailing list that people could subscribe and unsubscribe depending on their involvement? New organizers would not start from zero with zero people, old organizers would be free to stay around and give some advice, and those that support event after event could be always there, ready to help as well.
Yes, there would be little nuances, like having to resort more to English, and creating potentially more "noise" for people interested in a single event (i.e. when the EU hackathon and Wikimania's need to be organized at the same time). However, the whole trend is moving toward using Phabricator for project management, leaving the role of the list more for the daily little things and misc support.