[A quick note of interest before I start the entry: I've just started twittering, if you care to follow my microbloggable exploits. --Regina]
"Bitch, please," I can hear you saying. "I've read Harry Potter. Or at least seen one of the movies. I know what muggles are. And I can tell from your sense of humor that you're a grade-A nerd, so you obviously do too, and have ever since that fateful summer in high school that you were volunteering at a summer reading program for kids at the library and picked up HPatSS to stay on top of things."
No, friend. You do not know what "muggles" means, and neither did I.
In the 1920s and 30s, "muggles" was a slang term among jazz musicians for cannabis. Louis Armstrong, who was "an enthusiastic user of marijuana," to quote the article, wrote a song called "Muggles" about his beloved pastime, which is what the article in question is about.
Here's a link to the song, courtesy of Songza.
Now, I'm not saying that J.K. Rowling is trying to get children addicted to anything beyond Harry Potter merchandise. I just think it's a hilarious coincidence, or perhaps a sly (and by "sly" I mean "obscure to the point of being nonsensical") reference.