I have mixed feelings about this feature actually. It's super handy and nice when browsing the Web while going through a lot of pages in a short amount of time. When using proper Web apps it's a total pain + sometimes the history API is not supported correctly so you lose the context entirely (which means you have to start from scratch in whatever app you are using).
Gestures in general should be something standard, cross platform / cross browser with a nice API exposed to JavaScript. However, I understand why it's not, they were a mess on Linux until very recently, it's all over the place on Windows, support depends on the hardware, they are not very intuitive, etc.