If you are watching YouTube videos in a second browser window while you work, you are doing it wrong (unless you happen to have a huge display).
Adding items to the Finder sidebar and Dock in OS X is one more thing that shortcuts can make a bit easier.
Not sure where you find your music, devices, TV shows, or playlists in iTunes 11? You can restore the traditional sidebar view.
If clicking Finder sidebar items doesn't properly show their contents, then you may need to clear some settings files.
Bing's Social Sidebar lets you query your Facebook friends, and it now lets you tag any of your friends instead of only those Bing suggests.
The latest version of iTunes seems to have done away with a feature that many people have come to use regularly: the Genius sidebar. Instead of a Genius sidebar with options for finding new songs based on the ones in your library, there is now a Ping sidebar that gives you access to the social network's ratings and purchasing options.
One of the changes in iTunes that a number of people have been accepting with disappointment is the lack of colors in the sidebar, making the window look out of focus and a bit bland. Some people have looked into hidden settings and other ways to modify the iTunes program to bring the colors back.
Sometimes the OS X Finder can show a few odd folders in the sidebar under the Shared section. There are several ways to manage these folders, which in fact are only available systems on the network.
Sometimes the special burn folder the Finder creates to manage optical discs will not disappear when the disc is burned or ejected, resulting in an accumulation of them in the sidebar over time.
The latest update to iTunes 10 fixed a few known bugs with the initial release, but as expected Apple did not change the gray color scheme of the icons in the sidebar.