kudos have actually been patented in a certain context of computergames:
https://patents.google.com/patent/US20020188361A1/en
https://patents.google.com/patent/US20040224742A1/en
I remember vaguely that there was a lawsuit about the use of kudos in video games, but it was more than fifteen years ago and I can not find it back except this patent (in my memory there was a pre-2000 rally racing game that handed out kudos). Currently kudos, style points, seem to be very normal.
The problem for SE is that they do not seem to use patented technology. See also Are There Concerns About Copyright Violations?