1) Mac - App Exposé: In Lion you can swipe down with four fingers to activate App Exposé. This is very useful for when you have multiple windows open in the same application and need to quickly select the one you need. To turn this gesture on as well as customize it go to System Preferences, Trackpad, More Gestures.
2) PC - App Launch: In Windows 7 you can use a three finger press on the trackpad to launch a specific application. This gesture is great for a frequently used application like a plain text editor. To activate this gesture and the other Windows 7 gestures go to Control Panel, Mouse Properties, Device Settings, Settings.
3) Mac - Show Desktop: We frequently save files to our Desktop that we need access to when working on a project and this gesture which is performed by spreading the thumb and three fingers is very useful for seeing what is on our Desktop at a glance.
4) PC - App Switching: To quickly switch between open applications you flick four fingers across the trackpad. We use this one frequently while researching and writing.
5) Mac - Mission Control: Swipe up with four fingers to activate Mission Control which for those unfamiliar with Mission Control is like toggling between applications on steroids. Mission Control shows you at a glance mini windows of the various applications you have running and allows you to quickly select which one you want to work with.
6) PC - Side Scroll: Use a three finger flick to quickly scroll through images in a photo viewer window. This gesture makes locating the images you need a snap.
5) Mac - Look Up: Use three fingers to double tap on any word to look it up. We have always been a fan of the built in dictionary in OS X and this gesture makes accessing definitions all that much easier. To activate this gesture go to System Preferences, Trackpad, Point & Click.
What gestures do you use to be more productive?
(Images: Joelle Alcaidinho)