Jitouch is described as 'Software that adds extra, essential, and the missing gestures to your MacBook Multi-Touch Trackpad and the new Apple Magic Mouse' and is an app in the system & hardware category. There are more than 10 alternatives to Jitouch for Mac, Windows, Linux and Android. The best Jitouch alternative is BetterTouchTool. It's not free, so if you're looking for a free alternative, you could try Middle Click or GestureSign. Other great apps like Jitouch are Multitouch, Swish, Middle and 1Piece.
Too many options, but not one for diagonal swipes or letter forms, which I loved