One of the nicer but relatively unknown features of Mac OS X is its ability to create text clippings. Text clippings are basically selections of text that have been saved for later, and can be dropped into another document (or even a form box in a browser) at any time. It's a bit like the layby version of Copy and Paste, and all you have to do to create one is drag some highlighted text to the desktop.Text clippings can be kept indefinitely. If you have some clippings sitting around, and don't know what's inside them, you can take a peek by clicking on one and hitting the space bar to invoke the Quick Look function. You can also open one by simply double-clicking it, which will allow you to highlight specific text inside it to copy the regular way — if you only want a snippet of the larger snippet.
Shortcut of the Day highlights a great shortcut on various platforms from the desktop to mobile devices to the web. You can find more shortcuts here.