In the past, no feature of Windows packed more frustration per square inch than the System Tray. It quickly grew dense with applets that users did not want in the first place, and many of the uninvited guests employed word balloons and other intrusive methods to alert users to uninteresting facts at inopportune moments. At their worst, System Tray applets behaved like belligerent squatters, and Windows did little to put users back in charge.
In Windows 7, applets can't pester you unbidden because software installers can't dump them into the System Tray. Instead, applets land in a holding pen that appears only when you click it, a much-improved version of the overflow area used in previous incarnations of the Tray. Applets in the pen can't float word balloons at you unless you permit them to do so. It's a cinch to drag them into the System Tray or out of it again, so you enjoy complete control over which applets reside there.
More good news: Windows 7 largely dispenses with the onslaught of word-balloon warnings from the OS about troubleshooting issues, potential security problems, and the like. A new area called Action Center--a revamped version of Vista's Security Center--queues up such alerts so you can deal with them at your convenience. Action Center does issue notifications of its own from the System Tray, but you can shut these off if you don't want them pestering you.
All of this helps make Windows 7 the least distracting, least intrusive Microsoft OS in a very long time. It's a giant step forward from the days when Windows thought nothing of interrupting your work to inform you that it had detected unused icons on your desktop.
File Management: The Library System
Compared to the Taskbar and the System Tray, Explorer hasn't changed much in Windows 7. However, its left pane does sport two new ways to get at your files: Libraries and HomeGroups.
Libraries could just as appropriately have been called File Cabinets, since they let you collect related folders in one place. By default, you get Libraries labeled Documents, Music, Pictures, and Videos, each of which initially directs you to the OS's standard folders for storing the named items--such as My Pictures and Public Pictures.
To benefit from Libraries, you have to customize them. Right-click any folder on your hard drive, and you can add it to any Library; for instance, you can transform the Pictures Library into a collection of all your folders that contain photos. You can create additional Libraries of your own from scratch, such as one that bundles up all folders that relate to your vacation plans.