The way it works: first the the user prepares the board. The querant creates a 2x2 grid of answers, where the bottom left and top right are identical, as are the upper left and bottom right. "Yes" and "no" are good answers to put down. Next the postulant lays a pencil down along the x axis divide, then places a second pencil atop the first one, aligned along the y axis.
Next, the user gazes upon the pencils and paper, speaking a question preceded by the invocation "Charlie Charlie". As in: "Charlie Charlie, will I ever learn what's causing the severed foot phenomenon?" Charlie may refer to a demon or other spirit, whose assistance enables the query. Sooner or later, the top pencil will waver and indicate one pair of answer boxes. Creepiness results, or at least confusion and excitement. Don't forget to close the circle.
Charlie Charlie merits Infocult's attention because of its uncanny nature, obviously. At least one American cleric has denounced the practice for being bad witchcraft, as has a Vatican priest. Jamaica's education ministry banned students from playing.
Charlie also draws our gaze as a fearsome digital media event, since the craze only took off in a big way once it hit social media (heck, even Time magazine noticed; could Charlie be over already?). Vine was a popular place for Charlie videos, then YouTube, and now the Twitter hashtag CharlieCharlieChallenge aggregates a vast swarm of examples, questions, and reactions. So Charlie is now an internet thing, especially for young folks. Let's see if it gets the cyberfear treatment.
There may be a hoax/ARG aspect to CharlieCharlie as well, since at least Wikipedia claims the phenomenon was spurred as viral marketing for a new horror movie.
Additionally, there's a hispanic culture angle. Some players deem Charlie a Mexican demon, which seems unlikely. But there are signs the game or precedents appeared in Mexico and the Dominican Republic, before hitting the anglophonic world. Nice to see this Gothic transmission route operating again.
One more note: the utterly low-cost nature of Charlie makes it an apt oracle for our economically shambolic time.