Summarizing a long document into a few lines!
A cool feature hidden in the Services menu (for Cocoa apps only, not Microsoft apps!) is the "Summarize" function. It uses a complicated algorithm to transform a long text and summarize it into a short paragraph. I wasn't convinced this would really work at first, but after using it, it works great. There is unfortunately no keyboard shortcut but you simply have to highlight some text and choose "Summarize" in the service menu! Screenshot: