Among Microsoft Windows 7's features, a taskbar overhaul is arguably the feature in Microsoft's upcoming OS that has aroused the most interest. But it's also the most cloaked in mystery, as it was not part of the pre-beta Windows 7 software handed out to attendees at Microsoft's PDC (Professional Developers Conference) last month.More taskbar details emerged late last week on Microsoft's Engineering Windows 7 blog. Despite some criticism that the Windows 7 taskbar looks too visually similar to the Mac OS X dock, Microsoft does seem to be trying to break new ground with the look, feel and functionality of the Windows 7 taskbar. It's different, yet familiar, as Microsoft emphasizes in the blog post. Time will tell if it is actually better.Check out the blog post for more details on new features such as Jump Lists, Interactive Grouped Thumbnails, Aero Peek, Thumbnail Toolbars and Color Hot Track. The goal, as always, is faster and easier management of application windows. But this time around, Microsoft may be adding visual flair and the coolness factor to its list of goals. Just don't tell that to Mac users.Here's a summary of the four most notable new Windows 7 taskbar features:Unified Quick Launch and TaskbandMicrosoft has merged Quick Launch and the taskband into a big happy launching and switching family. Buttons in the Quick Launch bar that open a program (for example, Internet Explorer) turn into a window switcher when launched. This may not be a new concept, but Microsoft says that the difference with Windows 7 is that no matter how many, say, IE browsers you have open, and whether or not they are minimized or maximized, there will only be a single representation of IE on the taskbar. This is the default setting and you have the freedom to have as many buttons as you want.Microsoft also says that the Quick Launch\/taskband union allows one of the most requested features to be put into play: the ability to move taskbar buttons. Quick Launch has always allowed this, but now you'll be able to move running windows around.Interactive, Grouped ThumbnailsThe Windows Vista taskbar shows corresponding thumbnails when you mouse over a taskbar button, but in Windows 7 these thumbnails are clickable, allowing you to open, close or switch between windows right from the thumbnails. Also, each thumbnail looks like a mini version of the window it is representing, be it a Web browser, Word document or Power Point application.Microsoft compares this feature to having a "contextual Alt-tab surfaced directly off the taskbar." Windows 7 will still allow you to have individual buttons for each window if you so choose (though I wonder why anyone would want this, given the disorganization that ensues when button after button lines up in your taskbar). With the interactive, grouped thumbnails in Windows 7, Microsoft may have finally uncluttered the frequently cluttered process of managing and switching between windows.Aero PeekThe functionality of Vista's Aero graphical interface has been extended. The "Aero Peek" feature in Windows 7 should come in handy when your thumbnails are e-mails or Word documents with text and details that are too small to recognize. Why squint if you don't have to?Aero Peek displays the actual, full-size window on the desktop of the thumbnail you are hovering over. Not only that, but all other windows open on the desktop become transparent\u2014or turn into "glass sheets" to use Microsoft lingo\u2014so you can focus quickly on the window you want. A video demonstration from PDC 2008 of Windows 7's interactive thumbnails and Aero Peek feature.\n\n\nPeek also works on the desktop. The "Show Desktop" control has been moved to the far right of the taskbar. If you mouse over the control, all windows on the desktop turn to glass, allowing the entire desktop to be seen. This is perfect for times when you just want all those windows you have open to go away immediately.But thankfully you can get them all back just as quickly.Jump ListsJump Lists are new to Windows 7. If you right-click on a button in the taskbar, you get a mini-Start menu containing recently opened documents or various tasks associated with an application. Examples include recently opened documents in the case of Word or Excel or recently or frequently played music in Windows Media Player.Jump List: Right-clicking on Word gives quick access to recently used documents.\n\nThe advantage of Jump Lists, according to Microsoft: you don't need to start a program to quickly launch a file or access a task, you just right-click on a button. Also, the files in the Jump List don't take up space on the taskbar; they are automatically organized by their respective program in a list.By default, the Jump List contains a program's shortcut, the ability to toggle pinning, the ability to close one or all windows and a program's recently used files. If you want to keep a specific file or document around, you can pin it to the Jump List.