Long list of modifier keys for MacOSX…

E.g. by using Command (the Apple key) you can then do the following:

• Click on dock items to show in Finder
• click on spotlight results to show in Finder
• Drag items out of the dock to created copy in Finder
• Open link in new tabs in Safari, including forward and back buttons.
• Open Finder folders in a new window. This works with sidebar items as well.
• Drag toolbar items to remove or reorder in toolbars.
• Drag menu bar items to reorder them or remove them completely.

http://www.macosxhints.com/article.php?story=20070415081451932