The Pull to Refresh action is a common gesture for mobile apps -- used by the likes of Twitter, Facebook, Tweetbot, and Sparrow for a variety of commands. It may soon be a lot less common if the USPTO grants Twitter's patent request.
Loren Brichter filed for the "User Interface Mechanics" patent back in 2010, when he still worked for Tweetie (and before Twitter bought the company). The application described,
A method, comprising: displaying a content area; receiving input associated with a first command, the first command including a request to scroll the content area; and based on the first command, performing a second command, the second command being independent of the first command
That broad definition of a pull doesn't just cover the refresh command -- if granted, it would give Twitter a patent over any sort of pull-like gesture regardless of what command the motion activated, not just refreshing a feed. Given the ubiquitousness of the Pull-to-whatever system, however, this hopefully won't make it past the prior art phase. If it does, get ready to do more tapping, swooping, nudging, bumping, circling, and a litany of other silly gestures on account of this asinine IP arms race. [USPTO via iPodNN]