Due to the rapid advent of multi-touch user interface, so many companies are now providing their own gesture sets.
Jonathan Brill posted an interesting article on the need of a standard multi-touch gesture library. Especially, he wants Microsoft to publish a de facto standard gesture library with a community common license.
I totally agree with him. But I am not sure if it is possible to make an easy-to-use and remember gesture set without IP violation. For example, Apple has a patent that claims two-finger open- and close-pinch gestures and many other companies also have filed their own multi-touch gestures.
I just hope relevant companies well resolve the IP problem for the rest of us not to use clumsy multi-touch gestures.
PS: I like PQ Labs gesture set. Their multi-touch gestures seem to be useful to navigate 3D virtual world.