From Mario Fan Games Galaxy Wiki

The WIP/Sketch sub-forum was created on the 17th November 2007 by Yoshiman along with the Sprite Rips sub-forum. It's purpose was to section off the Arts Board to make it easier to navigate. The WIP/Sketch forum handles WIP art and simple sketches (that could also be considered a Work-In-Progress).

Like the Sprite Rips forum, it is currently in a trial stage and may be removed if it proves to be unpopular or useless. After being on trial for over a year, it was eventually merged back into the main Arts Board.