"BumpTop (for both Windows and Mac) will no longer be available for sale. Additionally, no updates to the products are planned."
Google's plans for the organizing software are uncertain but the growth in mobile could indicate a direction. The simple fight between Apple and Google for the best interface could also come into play.
We described BumpTop when it first launched as "a physics driven 3D desktop environment with an innovative menu system."
"Among some of BumpTop's most interesting features are its innovative, free-form method of selecting items on the desktop, the ability to flip through piles of files (with your mouse-wheel, or through an actual flipping motion if you have a touch-screen), and its highly intuitive pie menu system"
Wellington Financial estimated the sale at $35-40 million.