This is Everybody Dance Now, a video demonstration of a motion transfer system developed at the University Of California, Berkley that can apply the body motion of a source subject to video of other people. Right now it isn't performed in real-time (it takes a couple minutes of frame-by-frame rendering), but I imagine that will be possible in the future. No word what the illegal face-swapping celebrity p0rn makers think about all this, but the last time I checked they were shooting off fireworks and opening champagne.
Keep going for the video, which, while not perfect, is still very impressive. Full paper on the system HERE if you're interested.
Thanks to Christian, who agrees soon nothing will be real.