NetNewsWire, a superb free RSS reader for the Mac, syncs with Google Reader but doesn’t have a built-in way to share news items. I installed this AppleScript and used the Keyboard System Preference to set its keyboard shortcut to ⌥⌘S. That command normally invokes NetNewsWire’s “Add to Clippings” key, which I think really should be tied to Google Reader’s share feature. I also added “activate” before the last line of the script to bring Safari to the front when I share an item.