Hit ⌘-space on your Mac and a window pops up asking for instructions. If you don’t hate yourself, the window is from an app like Launchbar or Alfred, and not from OS X's built-in Spotlight. Launchbar does everything Spotlight does, and then some, letting you browse inside text files, mail search results and browse your iTunes.
And now it brings something called Staging Area, which is just like Quicksilver’s old “comma trick.” Search for an item, and instead of telling Launchbar to act on it right there, you hit the comma key and it is added to a buffer. Add more items every time you hit the comma, and then act on them all at once. Currently only available in a nightly build of v6.1, this should be coming soon. €24