I plug a [USB to PS2 converter](http://www.google.com/products/catalog?q=usb+to+ps2+mouse&cid=14941124492437992702&ei=6lSSTO3KFYPUiwTw4rhp&sa=title&ved=0CAcQ8wIwADgA#p) into my computer and then plug a [PS2 to USB converter](http://www.google.com/products/catalog?q=%22usb+to+ps2%22&cid=14511876331776421736&ei=flSSTOrRL5HCigSpnYlh&sa=title&ved=0CCUQ8wIwAjgA#p) (different brand) into that and then plug a thumb drive into that... and the drive works. 

What the heck?! Is USB somehow electronically backwards compatible with PS2 and they are just pass through devices?