...with the basis of the show, Robert J Sawyer's novel Flashforward (1999). In the novel, the cause is a CERN experiment to find the Higgs boson.

I suppose one author might have read the other (Great Shift stories started being posted in 1998, according to FM), but inasmuch as the causes are different (one individual in GS, a large science organization in FF), I'd guess that they were thought up independently. It doesn't seem like that unique a concept, and it's not too different from older stories -- I'm thinking of one, written in the very late 1960's or early 1970's (can't remember the author now -- Robert Silverberg?) -- where something in the drinking water wipes out everyone's latest year of memories, except for some radical right-wingers who only drink bottled water.

Eric