So instead, I pull up Quicksilver, intending to open Scrivener and pin it to the Dock while it's open. I call up Scrivener in the direct object field and I'm just about to hit Enter when I think, "Wait a second..."
Hand to the trackpad. I grab the Scrivener icon and drag it down to the Dock—which separates to indicate I can drop it right there.
In summary: I love the Mac's ubiquitous drag-and-drop.