I was just sitting here a little while wondering if the asteroid WD5 missed Mars, and if it did, how much did its orbit change. Then I fired up my feed reader and saw that Emily wrote about this in her usual thorough and interesting manner, thus obviating any need for me to so, other than point you to her. So there. Bottom line, though: it almost certainly missed, but its orbit changed quite a bit, we probably won't recover it for years, but it's a small rock and space is big, so it doesn't pose much of a danger to anyone.
So, any doomsday criers out there (I'm looking at you, TU24dotORG): give it a rest.