Speaking of Unread, Jared Sinclair wrote a post detailing his decisions behind the app's design:
“I decided that best way to make Unread a comfortable app was to let the reader directly manipulate each screen anywhere her thumb might land. This freed me to remove interface chrome and focus on the text. It’s now a trite idea for design to focus on “content,” but in Unread’s case it really was an essential goal. I wanted readers to get their minds out of the email rut that has trapped their expectations of what RSS can be.”
I think he nailed the comfort aspect. The gestures in Unread feel so natural that I'm finding myself swiping around and exploring every corner of the app just because I enjoy the sensation of flicking things on- and off-screen.