According to Microsoft, there are literally of thousands of improvements in the Windows 8 Consumer Preview. But if you're familiar with the previous milestone, the Developer Preview, and only want a high-level view of the major changes, go no further. Here's a comprehensive list of the most important changes Microsoft made to the Windows 8 Consumer Preview. Some are obvious, sure. But some may surprise you.

Note: This is by no means a complete list, and of course you should check out my many other Windows 8 Consumer Preview articles for even more information about the changes in this release.

Semantic zoom. At the BUILD conference last September, Microsoft showed off a cool feature called semantic zoom but then revealed that it wasn't included in the Developer Preview. Well, it's here now: Semantic zoom lets you pinch on the Start screen so that you can display its entire length in a single, miniaturized screen. And from there, you can quickly navigate to the Start screen group you want, select and move entire groups, and name a group.

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Editing a group on the Start screen while in semantic zoom

Fun fact: Semantic zoom is actually a feature that app developers can add to their own solutions. It doesn't have to work exactly as it does in the Start screen, but is rather generally available as a way to perform some action in the context of the current UI.

Notifications. In the Consumer Preview, apps can display notification "toasts", small windows that appear in the upper right area of the screen so as to be non-intrusive. You configure notifications in the Metro-style Control Panel, and can do so globally and/or on an app-by-app basis.

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New notification toast

Fun fact: The Developer Preview included a second type of notification, which is system wide and still present in the Consumer Preview. This notification type, called a flyout, covers the middle part of the screen with an accent-colored bar and must be addressed in some way before you can proceed.

Switcher: The new app-switching experience. The Developer Preview offered only a basic way to switch between the running apps, using a flicking gesture from the left edge of the screen or the old fashioned ALT + TAB keyboard shortcut. In the Consumer Preview, the new Switcher UI has been added, providing a consistent way to switch between apps and also manage them. You invoke Switcher by swiping in and then down from the left edge of the screen, or by mousing into the top left corner of the screen and then down. Switcher presents thumbnails for each running app. You can click or tap one to switch to it, pull an app out and down to quit it, or rearrange the order of apps using touch or the mouse. To return to the Start screen, tap or click the Start tip at the bottom of Switcher.

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Switcher (on the left)

Fun fact: Switcher will include active, suspended, and closed apps.

Microsoft account integration. By logging into to your Microsoft account (and not "Microsoft Account"), formerly called your Windows Live ID, you can synchronize your entire Windows 8 experience across multiple PCs and devices. This includes PC settings, personalizations (colors, backgrounds, lock screen, account picture), desktop personalizations, ease of access settings, language preferences, app settings, browser settings, Explorer and mouse settings, sign-in information, and more.

Fun fact: You can logon to a domain or local account and then connect it to a Microsoft account to achieve the exact same integration.

SkyDrive integration. If you utilize a Microsoft account, the aforementioned settings synchronization will occur through the Microsoft SkyDrive service, as will integration with the Windows 8 file picker, the Photos app, and more.

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SkyDrive integrated into the Photos app

Fun fact: More SkyDrive integration pieces are coming in the future.

Consistent Charms access. In the Windows 8 Developer Preview, Microsoft offered separate and distinct interfaces for accessing the Charms from touch and from mouse and keyboard. These are now consistent in the Consumer Preview, in that the Charms always appear on the right side of the screen. Accessing them is more consistent, too. With touch, you swipe in from the right edge of the screen. And with a mouse, you mouse into the top right or bottom right corner of the screen.

Fun fact: The Show Desktop button was removed from the Windows 8 taskbar to avoid confusion with the Charms. 

Start preview thumbnail. As you know, the Start button was infamously removed from Windows 8 so that the Start experience would be consistent between the desktop and the Metro-style Start screen. But it's been replaced by a new Start tip, called the Start preview thumbnail, that provides the same functionality.

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No Start button? No problem

Fun fact: Right-click (or tap and hold) on the Start preview thumbnail to discover a handy menu of Explorer features that were previously hidden in Windows 8. 

Start screen improvements. Aside from the aforementioned semantic zoom, Microsoft has made a number of improvements to the Start screen. There's a new hidden App bar (swipe up from the bottom to view) that provides access to the newly restyled All apps list. There are much better pinning features, including the ability to pin any executable, web site, contact, and more. Mouse users can use a new feature called Push to scroll to quickly zoom from one end of the Start screen to the other by pushing up to an edge of the screen.

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Improved pinned tile editing in the Start screen

Fun fact: Push to scroll will scroll quickly if you move the mouse quickly and slowly if you don't. 

Metro-style apps improvements.  Users can now close Metro-style apps, a frequent request of Developer Preview testers. You can do so using the keyboard (ALT + F4) or by swiping down from the top of the app screen to the bottom.

Fun fact: As you swipe down to close the app, it will turn into a thumbnail and then disappear into the bottom of the screen in a little woosh.

New App Previews. Where the Windows 8 Developer Preview included a fairly lame selection of preview apps that were designed by college interns, the Consumer Preview includes useful, full-featured apps. However, these apps are not complete, and are far rougher (and thus less reliable) than the system itself. Included App Previews are Xbox Live Games, Bing Weather, Bing Maps, Calendar, Mail, Videos, SkyDrive, People, Photos, Music, Messaging, Camera, Bing Finance, and Xbox Companion. Two neat games are also included to show off the power of the developer platform, Pinball FX2 and Solitaire, though these are not technically app previews.

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Bing Maps

Fun fact: Pinball FX2 was written in DirectX while Solitaire was written in HTML, CSS, and JavaScript. 

Internet Explorer 10 improvements. IE 10 gets a number of nice improvements in the Consumer Preview. There are numerous panning and zooming improvements, including keyboard-based zoom and double tap zoom. You can now swipe directly on the page, to the left or right, to trigger Back and Forward navigation, respectively. A new InPrivate button on the Tabs bar lets you open a new InPrivate tab more easily. And IE's settings are now available via the Settings charm.

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The Metro-style version of IE 10 displaying the best Windows site on the web. :)

Fun fact: While it's a little weird that Windows 8 includes two versions of IE 10, it can come in handy if you're using the Metro version as your primary browser, since that version doesn't support add-ins. So if you navigate to a web site that requires an ActiveX control, IE 10 Metro will let you switch to Internet Explorer 10 on the desktop, and then automatically do so for that site in the future. 

System-wide spellchecking.  This one is pretty cool: Windows 8 includes spellchecking as a platform service. So any app that uses standard Windows text controls will get spellchecking functionality automatically.

Fun fact: Users have often complained that Internet Explorer doesn't include integrated spell checking. But now it doesn't have to because the entire OS has it.