When reviewing papers, I usually try to note which ones are written in Word, since this usually correlates well with a bad paper. It's usually pretty easy -- although body text in TNR looks quite similar, italics, mathematical notation and subscripts are usually clear indicators. Lately though I seem to have been finding it a little tricker to tell at a glance. So I've resorted to checking one clear indicator: ligatures. I'm sure it's possible to insert ligatures in Word, but no-one ever does it, so a quick search for ff or fl helps resolve the matter.