Back in the day I would log onto yahoo chess and beat everyone by simultaneously playing expert mode in windows chess and just mimicking the expert modes moves on yahoo as mine. Good times, never lost.
People still do that in chess.com. It is really annoying, because even if you are good enough to beat the computer, playing against a computer is very boring.
A few hundred? Hundred thousand, maybe. Here are several sites where volunteers run computer chess tournaments 24x7 and publish the resultant rating lists.
No seriously
https://en.wikipedia.org/wiki/Kasparov_versus_the_World