Yikes and Gadzooks! Firefox 4 disables pinch zooming in OS X. I thought something was broken. You have to go into about:config to put it back. If you've never used about:config, you'll see a tongue in cheek "warning" about voiding your warranty. Ignore it. Uncheck the box so you won't see that so-called warning again. To change the values, two-finger-click or control-click anywhere on the preference and choose "Modify" from the context menu. The silver lining for me was that typing in pinch and pressing enter also displayed browser.gesture.pinch.threshold, which sets how far you have to pinch for the zoom to register. I didn't know that setting existed. The default value is 150. I'm trying it at 75. RoCo, maybe it's time for you to set up a new Firefox profile. A tired old profile is frequently the cause of Firefox slowness. Before doing this, be sure to have critical information backed up, especially bookmarks. Extensions will need to be reinstalled. I created a new profile in conjunction with installing Firefox 4. Before doing that, I set up a Firefox Sync account in 3.6 using the Firefox Sync extension. This allows you to save your bookmarks, passwords, preferences, history, and tabs in the "cloud" for syncing across computers. You won't need to install the extension in Firefox 4 because Sync is built in. Before removing your old profile, be sure to save your Sync Key. You'll need it (in addition to your username and password) to set up Sync in a new profile. I only synced my history and preferences. My bookmarks are synced with Xmarks, and I don't have any saved passwords.