What is "parapublishing"?

The site from which the above statistics came offers (for a price) advice on being your own publisher. I imagine that the stats are provided to convince would-be authors that a vast, untapped market exists for those manuscripts that keep getting rejected by the commercial publishers.

Books literally sell by the ton -- I've seen the trucks backed up to the loading dock at Chapters, and the queues at the cash desks. What proportion of them contain information that readers find useful or even entertaining? Good question. Today's Great Canadian Novel is tomorrow's unreadable pulp, and today's dynamic self-help tome is tomorrow's pack of lies.