Two weeks ago, blogger Andrew Hearst, well-known in the industry for his magazine-cover parodies, posted another offering on his site, Panopticist.com. Hearst's latest was a takeoff of teen-girl bible Seventeen, re-imagined as a book for teenage boys called "Sementeen."

Yet a quick scan of newsstands reveals that Hearst has imagined not only a title but an entire genre: in a space crowded with books like Seventeen,...