Empty space? No problem!
Just let admins put blocks in there to hold other content, highlights for important articles, links to other parts of the site, relevant advertising etc.
There's a reason why so many larger forums go to a right column layout, actually there's several reasons, but the point is we really should have a way to build/use a right column out of the box, 300x250 ads are the best paying adsense format, and have been for awhile.
I'm hoping/assuming that, based on the presence of multiple widgets/info boxes in the right column already that we'll have the ability to arrange what order things show and add our own custom choices to show there.