Firefox 4 has come out, and it’s quite impressive, but for Mac OSX user that do pinch/zoom regularly with the trackpad will find out that it’s not possible anymore. Luckily, there’s a work around to enable that
– Open a new Tab and type in "about:config" (without the quote) in the address bar
– You will be asked to confirm to continue. Do it
– Search for the term "pinch" (without the quote).
– Edit the pinch.in & pinch.out as followings: