OS X Lion changes default scrolling with Magic Mouse.
So after waiting over a half hour to download OS X Lion from the App Store I got it installed. The install process took about 15 minutes on my 2010 Core i7 iMac. After starting up OS X Lion and starting to use Safari I almost freaked out as scrolling on my Magic Mouse did not work anymore. I would move my finger towards me and the page did not move. I dove into the Mouse preference and their is this new scrolling option called natural. This option means that the content tracks finger movement. Well I am totally not used to this yet and I ticked it off.
Next thing to get used to is the new email client. I definitely like the new three column layout, which is no problem on a 27-inch iMac. There are many more features to explore and incorporate in the daily work flow. In case you get confused right away with the scrolling though, you now know what to do.