Part of the reason (imo) that kids are so open to making new series a 'phenomenon' is because of the doors that J.K.R. opened for kids. Many, many wonderful books have been released over the years for children before HP, some much better than the HP series, but did not hold the appeal they did for some reason or another. Not that I'm berating these authors for their talent but I do believe that children/teens would not be reading to the extent they are now if it were not for the HP series.
When I was growing up I was the odd one out for the amount of books I read. To this day when I run into some of people I know from elementary/junior high and stop to chit chat it's evident that they never progressed past See Spot Run. In high school I found more people that were well read, or even read for that matter. I was involved in a sorta book circle of girls where we all read and traded romance novels with each other. I love my job because EVERYONE reads. I mean it. I can just start talking about some book and chances are two people there will have read it and within the next few weeks two more will have. I love that for all the shit people talk about waitress and how it's not a "real job" these people are more intelligent and open minded than most people I know.
Had a yummy vegan lunch today with Aviva and then went to Whole Foods. I only brought in $20 for fear of spending more and spent exactly $19.19. I rule!