Soyface is more generalized. Mostly it came from more innocent Reddit-esque selfies where someone who looks like he posts on Reddit would take a picture with something and would make an excited open mouth face (because men don't know what to do when having their picture taken). After 1,000 variations of some beardo looking overly excited, mouth agape, at his newest Starlord funkopop, the soyface as we know it was named. The same expression also became the default youtube thumbnail expression for every "content creator", especially mr beast