Michael W. Lucas posted about his results selling an early edition of his recent DNSSEC book through Leanpub.  He lays out all the numbers in detail, the sort of thing I love to see.  The idea of self-publishing and open source go hand in hand, but the idea of that selling is often talked about in speculative terms rather than concrete.  He’s now opening his own direct sales store, which hopefully means more direct BSD material.