While Orton didn't always use the clap signal, he began adopting it towards the middle portion of his career, when began using one of his trademark moves, the Snap Powerslam, at a consistent rate. To the naked eye/fan unaware of its significance, the clap before the powerslam is nothing more than a mere tic, something Orton has become so accustomed to doing before the move that it's now become part of the move itself.

This is again where close viewers of Orton can spot the difference. Like any wrestling move, there are times Orton goes for the powerslam, but either has it blocked or reversed by his opponent. What's the difference between that and when Orton hits it? Simple; Orton doesn't clap when his opponent is supposed to reverse the move. As such, the clap has become Orton's way of "calling the match so to speak," with the clap being used to signal to his opponents when they're about to take the powerslam, while the lack of clap signals that it's time for them to block/reverse the move.

In a way, Orton's clap, which has since gone on to be adapted by several other pro wrestlers, is the evolution of a practice AEW's Jake Roberts started in the 80s. Much like Orton claps before his powerslam, Roberts always made a point to slap the back of his opponent before hitting him with his trademark DDT, and always failed to slap the back before his opponent countered the move. All of this was for a similar reason to what Orton does; the slap on the back would signal the DDT was coming, allowing the wrestler to properly prepare himself to take the move, while the lack of it signaled that it was time for a reversal.