We’ve noticed two more sites adopting the 4th Column approach to page layout: The NBA site, and Forbes.com. In both cases, this space is being used for added-value, personalizable content and functions. Each area requires free registration and is given a name intended to signal the value of this personalizable, portable, content area (The “NBA Fan Center” and the “Forbes Attache”). Forbes includes a 120 x 90 ad unit and pushes the idea further by making the Attache detachable (making it a Dettache?) so you can keep it open as you browse other sites or use other applications.
NB: We were not able to get the Forbes Attache to work in Firefox.