Phil Libin, Evernote CEO today said, that he doesn't spend a lot of time thinking about competition, but he admits that there has been one "age-old rivalry" - with pen-and-paper. Hearing about people who still take notes on paper is "infuriating," Libin said, in part because he still does it himself. "This is a fight that many people in the technology space have been fighting," Libin said.