In Sharon's dream world of Harry Barker, "luddie" is a truncation of "Luddite", a term used by hackers in both a descriptive and sometimes derogatory context to describe non-technical, non-hacker individuals. For fans of Harry Potter, "luddie" would be roughly analogous to "muggle". There is no true "luddie" organization per se, but the term is used to describe a classification of people and thus best fits within this category.
By and large, "luddies" do not know or otherwise don't care about what goes on in the high-tech world of hacking. While it is true that hackers occasionally gain attention of the "real world", for the most part the two groups exist side by side but never truly interfacing directly.