Create an automated newsletter that sends those who are interested an update of what has changed on the site and new things have been learned. If people rated an item high that was early in the delivery pipeline and now is either worked on or completed, people get a personal update on that. Show positive feedback from visitors and how it has improved their work, but also show critic and how that was translated into backlog items and now waits for community up-voting; if that doesn't happen, then it was not that big of an issue?