nostromo is right, that's how they did it. U see David levitating 2 or 3 feet in the air, the same way you see spiderman and jackie chan doing amazing stunts, and the reactions from the crowd is super imposed or acted out by actors wearing the same clothing. As you notice, the people close to blaine watching him, you only see their back side, you never see their faces and blaine being raised 3 feet in the air at the same time, then a second later, the camera shows you those real people's faces reacting to what happened, then cam gets shifted back on david, but like I said, never would you see him up that high and the crowds faces at the same time, only the backside of the crowd, in which doubles can be used. Again, the masked magician special on tv already showed us how David was able to lift 3 feet in the air like in that pic and other magic he did. David used this intricate mini pulley constructed in the card deck to raise the card from the deck, he uses a strong magnet block under the sleeve of his jacket to make the match dance on his arm, the match has this little metal inside the head part. David can't read minds, what they don't show you is that he is wrong a lot of the times, but just like gambling, eventually you will get some right, and they ONLY show the ones he gets right on tv and the ones he gets wrong, it ends up on the cutting room floor. Like I said, let him do that to you in person, he doesn't always pulls it off, but if you watch it on tv, they can edit things and only show the ones he gets right, making him look like a genius or someone inhuman.