Funny thing was that everyone was expecting it since Tobi's Sharingan was first revealed. Then later they just seemed to drop the theory and BAM! The masked man is Obito! xD
I know. He caused a war with the world because Kakashi killed his crush. "You were supposed to protect Rin!". That doesn't give him the right to do what he did. And now, Madara has revealed that it was him who set Rin up. How pathetic.