Very interesting article, indeed. I was wondering, could Snape put his memories in a pensieve before going to be with Voldemort. That could be how Voldemort doesn't know Snape's true intentions.
I am not sure I want to believe that Harry's scar is a Horcrux. I do believe that Voldemort did plant a Horcrux in Dumbledore's office when he went for the interview. It could be the sword, could be the hat, it better not be Fawkes, if the bird never dies, could the Horcrux ever be destroyed? Are there pictures of the founders in the office? Could he put one in Gryffindor's picture?
Doesn't a horcrux have to be made at the moment of a killing? Or do you think Voldemort had the horcrux object with him and somehow just hid it in the office? It couldn't have been created there, I don't think. I am still wondering about the Sorting Hat, which belonged to Gryffindor, but I think it is unlikely. I also have been wondering, does anyone know how Harry's parents and Neville's parents "thrice defied" Voldemort, per the prophecy? I think Dumbledore says only they were in the Order and had escaped three times.
I just don't think Harry's scar is the horcrux. I think the entire person or creature would have to be the horcrux, not just some physical feature of that person. As for the article, I don't think Hermione's failure to research Regulus Black is significant. As far as I can tell, Regulus was not a well known wizard; why would he even show up in the books? I can't recall if Hermione is even present when Sirius mentions his brother to Harry.