BumpTop is a 3D, multitouch desktop that’s been made available for both Mac OS X and Windows. What’s interesting about this acquisition is that it puts Google in command of technologies (and, presumably, patents) which might challenge Apple’s multitouch hegemony.

Things like double finger touches, pinch and zoom. User interfaces which are likely to be part of the definition of future tablet and mobile-based computing, in the post PC, mouse (and Flash) age.

We’re interested to see how this goes. Meanwhile the company is making its BumpTop Free software available for free download to Mac and Windows users for one week.

This is April’s fifth purchase by Google which also recently acquired, Episodic, Plink, Agnilux and Labpixies.

Via 9to5 Mac