I’m not sure where to start here.  In part the “obligation” comes from “the editors” own expressed concerns about the sustainability of the site.  If sustainability is a valid concern, then both costs and benefits must be considered.  While the editors of this and other sites might wish to do such considering in private, it seems to me that when a project is sustained by large amounts of public funds—grants and other—there is an obligation to be accountable to the public as well.  As to whether digital projects have an obligation that print publishers don’t, I would suggest that it is in part the unwillingness or inability to confront such questions has more than a little to do with the demise of so many academic presses in the last 20 years—they were economically unsustainable.  Yale’s press is private, and has little obligation to be accountable publicly; I feel differently about U Kansas Press and other publicly funded publishers—if they are selling only 8 copies of some of their books they’re making poor choices in the allocation of public funds.  Yes, I do believe there is an increasing moral obligation to be transparent about the deployment of such funds.  But no, I don’t fully walk the walk either.  My own repository does publish a budget every year, but we do not yet publish our site statistics, partly because the stats produced by our university’s preferred program are not very useful and we have not yet deployed a different program.  We do, however, publish many of our other “production” and “use” statistics—how many collections and cubic feet we process, how many researchers we serve, etc.  Website use is merely one more metric.