The first time I saw this was in the movie Revenge of the Nerds. There's a dinner scene where everyone has one hand full, so they snap instead of clap. This is probably not "prior art" per se, since the snap was due to necessity, not some cool new concept.
It isn't even a "cool new concept" in the context of the article. It's been used like clapping since at least the beatniks, and possibly since Roman times.
Similarly, orchestra musicians will stomp their feet instead of clapping, since it is difficult to clap without dropping your instrument.
Snapping is, as far as I know, common in billiard. Or at least it was 25 year ago in billiard clubs in France.