Summarise text in any OS X aplication
1 Getting started
Since 10.7 (Lion), Summarize has needed activating before you can use it (most people don’t know it exists). Go to System Preferences > Keyboard. Select the Shortcuts option, and then click on Services on the left. Scroll down on the right until you find Summarize – it’s near the bottom.
2 Creating a keyboard shortcut
While Summarize is highlighted in the list, you can click the ‘add shortcut’ button on the right-hand side to give Summarize a keyboard shortcut (otherwise, it’s only available through the Services menu). This is extremely handy if you intend to be using Summarize frequently.