if you copied your current style to a new one, and called it, "StyleName - Hidden Columns" (or whatever).
then edited the new style to have the desired css at the bottom of the EXTRAS section, you could easily just switch your forum layout by changing your style
Just add these to that new/copied style's EXTRAS section:
.left_col{display:none;}
.right_col{display:none;}
But then again, a user could just go in to their My Stuff > Preference page and turn the columns off. That would be the best way. But it requires about three to five more clicks. One way is the obvious way, and the other way is a quick/fast way to toggle their display on all forum pages, including the portal.
Its all a matter of how you want to customize your forums. And UBB.threads lets you make your forums...yours
