QuakerQuaker is an obvious example. For the first few years it didn't take any more of my (Martin Kelley's) time than we might expect of a committed volunteer committee clerk. Even now it's only taking about a day a week of my time and less for other members of the Editorial Board. All told it's reaching over 5000 people a month, which qualifies it as a major publication. 

What other examples do you see? Are you working on some yourself or dreaming up some?