What do you mean Gesture?

Here's a neat trick for the MacBook users out there (yeah, both of you): use two fingers on the touch pad for scrolling. Turns out this is incredibly useful. If you've ever used a mouse with a scroll wheel, you know how useful this can be. I have to admit I find Apple's single mouse button thing a bit constraining. Now I can use two fingers on my track pad even if I can't do the same with the mouse buttons.

In computer science speak this is called a gesture. Back in the early 90s I remember getting a demo of another gesture based interface at CMU. If found it really cool but couldn't think of how it would be used in real life. I'm glad these ideas are making it into commercial products. It turns out the iPhone will also have a bunch of gestures built in. You can flick your finger across the display to scroll. Pinching your fingers together will zoom out. Spreading your fingers apart will zoom in. This is kind of hard to explain in print, check out the photos demo to get a better idea of how these work.

Not only are gestures coming out as UI components. The term is also starting to have a broader meaning. Lately I've heard folks use gesture to describe the act of tagging or the act of selecting an item from a list of search results. This strikes me as a strange use of the term. It's at least useful in that it makes us think about user interactions from a slightly different angle. Battelle likes to talk about search as users expressing their intent. In this context gestures could be thought of as further evidence of our intent.

It seems to me there are two kinds of gestures. One is a command and the other is evidence of intent. Pinching a photo of George Bush on my iPhone is a command, a direct manipulation. It doesn't mean anything really except that I'm done looking at the picture and I want to move on. Tagging that Flickr photo of Bush as velvety is a evidence of intent. It says something deeper about the relationship between me and the photo. What do I mean by the gesture of tagging our president as 'velvety'? In this case it's just something I find amusing. It probably also says something about my politics, but let's not go there. This is a technology blog, not a political blog after all.