When Apple announced that Lion would ship this month, the company went into detail about 10 features that it considered major reasons to upgrade. Apps that automatically save state on quit and files that save themselves are reasons enough alone to consider the $29.99 update, but some readers wondered whether they were better off sticking with Snow Leopard.

So, while we're all waiting to read John Siracusa's highly anticipated Lion review (expect it to go up this week!), we decided to dig into the under-the-radar goodies that Lion will offer among its "250+ new features" that might tip the scales in its favor.

Archiving e-mail

Much has been made about the new interface Apple is adopting for Mail, including its new conversation view. That might not do anything for heavy Gmail users, who have had such a view for some time via Gmail's Web interface. But the new version of Mail shipping in Lion also includes a two-click archiving feature to quickly move mail messages from your inbox to an archive folder for later reference. If you (like me) are constantly dealing with an overstuffed inbox that takes forever to load, the new ease of archiving important messages should offer a significant workflow and performance boost.

WebKit2

The version of Safari that ships with Lion will also be built using a new underlying engine called WebKit2. That improved WebKit engine is built to generate a separate process for rendering content, while the main process handles user input. This means that errant JavaScript or a buggy page won't freeze or crash the entire browser, so you can continue to work on other things while either waiting for that tab to stabilize, or simply close it and move on. The rendering process is sandboxed from the others and the rest of the operating system, offering greater security.

Chrome launched with similar features in 2008, and other browsers are beginning to adopt this model as well. However, we know that a lot of our readers use Safari, especially on Mac OS X, so it will be a welcome change.

Improved security

Speaking of sandboxing, Lion includes improved address space layout randomization (ASLR) as well as application sandboxing system-wide. This should improve the overall security of Mac OS X from errant hacking attempts, and it addresses a known security weakness that security researcher Charlie Miller has criticized for the last few years. While Leopard and Snow Leopard introduced limited ASLR, the implementation was incomplete and didn't offer full protection against library function attacks. THe new implementation improves security for both 64-bit and 32-bit software.

Merging folders

The Finder will gain several new features and interface enhancements in Lion. Among our favorites is the new Merge Folders option. If you try to drop one folder onto another folder of the same name, Lion will offer to merge all the files into a single folder. Similarly, you can select multiple files and folders and use the new Group as Folder command to quickly add all those files together into a new folder. As someone who likes a clean desktop but constantly manages multiple projects, these new features should make desktop cleanup so much easier.

Full disk encryption

Some readers have bemoaned that Lion is too much like iOS with the Mac App Store, Launchpad, and other iOS-like elements. We're not convinced this is necessarily a bad thing, but we noticed that Lion will gain at least one very useful feature common on iOS—full disk encryption. All the data on an iOS device in encrypted in the filesystem, and Lion's improved FileVault 2 adds that capability to Mac OS X. Instead of merely encrypting a user's home folder, the entire disk is secured with XTS-AES 128-bit encryption. FileVault 2 also adds an instant wipe feature should your machine end up in the wrong hands.

Unified iChat buddy list

Since many people rely on instant messaging every day, iChat includes a number of improvements to simplify using it with more than just AIM. Along with support for Facebook chat, Google Talk, and general Jabber services, iChat now also supports Yahoo Messenger. But instead of making you use separate buddy lists for each service, iChat on Lion now combines all your contacts into a single buddy list (à la Adium). Additionally, iChat has a new plug-in architecture to allow adding support for any chat service. These plug-ins run in separate sandboxes processes, so they shouldn't interfere with iChat's primary functionality.

Mac OS X virtualization

Finally, though Apple hasn't directly mentioned this feature, examination of the EULA for Mac OS X Lion has revealed that Apple for the first time allows Mac OS X client to be run under virtual machines. The license allows up to two additional copies of Lion to be run on the same machine simultaneously without the need for an upgraded license. This is likely due to the fact that Mac OS X Server is just an add-on to Mac OS X proper beginning with Lion. However, the change should be a boon to application and Web developers testing software in different environments, for instance, or power users who want to set up sandboxed environments for running new software.

These are some of the major features that stood out to us, and seemed to offer improved workflow options or better performance. Are there other features among the 250+ that stand out for you? Let us know in the comments, and stay tuned for Siracusa's review later this week!