Here is list of some of the things that Lion has that Snow leopard does not. Address Book now uses an iPad-like user interface AirDrop – direct file sharing via Wi-Fi Direct Auto-correction now behaves much like on iOS devices, displaying an iOS-like popup box Auto Save – As in iOS, documents in applications written to use Auto Save will be saved automatically so users don't have to worry about manually managing their documents Wow I'm going love the Auto Save. Full-screen apps – Native, system-wide support for full-screen applications. Supporting applications display a new button at the top right of application window, this button opens applications in full-screen mode May come in good for some apps that need to be full screen. iChat now has support for logging into Yahoo! Messenger. Users can audio- and video-chat with other iChat users using their Yahoo! accounts Nice Launchpad – An application launcher that displays an iOS-like icon grid of installed applications. It features the ability to make multiple pages and group apps into folders that function the same as folders in iOS I really love those the most. Mail 5 – Uses an iPad-like user interface Multi-touch gestures – Similar to iOS, additional gestures performed using a multi-touch input device Nice. QuickTime re-incorporates some features from QuickTime Pro. New features cited include Copy/Paste, Insert Clip, Crop Video, Rotate Video, Resize, Trim, and more Export options. Preview gains several features, including full-screen support and the ability to sign a document Resume – Applications resume in the same state when re-opened as already seen in iOS Safari – With full-screen mode and the new WebKit2 layout engine System Information – This feature is a re-design of System Profiler, which has been completely altered with new views which display graphical information on displays, storage devices, memory usage along with other hardware information. The previous layout remains available by clicking "System Report". Early builds of Lion also used System Information as a replacement for "About This Mac", although the final release reinstated the version of this dialog box found in Snow Leopard TextEdit gains a new graphical toolbar with font selection and text highlighting. The new TextEdit also supports Apple's new automatic file saving and versions technologies Versions – Time Machine-like saving and browsing of past versions of documents for applications written to use Versions wow this so cool. reviews why Lion is so good http://arstechnica.com/apple/reviews/2011/07/mac-os-x-10-7.ars/1 Wow I did not think Lion would have so many new things and such a change. What a big project that was.