Looks interesting, but I'm not sure I follow what you're saying... that screenshot is of a three-pane interface if I've ever seen one. Many RSS readers today look *exactly* like your screenshot (Notice I say "look", not "work", since I presume that, in particular, the buttons to the left appear to be different functions to those common in other readers).
Yeah, I know what you mean. After I re-read what I had written I counted 3 panes in my screenshot too and thought I should try and clarify.
I was talking about a top left pane with a collapse/expand folder hierarchy, a top right pane with a view of the selected channel displayed in a grid with rows and columns and a bottom pane displaying the selected article or item. Hope that clarifies.