In case anybody else doesn't see it immediately (it took me a couple of tries) -- the 'funny' bit is that it automagically appends "Read More: <link>" to your selection.

I haven't pored through their code, but I already know that my initial suspicion (binding CTRL+C with JS) isn't accurate, as right-clicking -> copy also appends it.

It's interesting at the very least, and I don't know how they're doing it. Anybody have an idea?