@pandascepter
Thank you for doing my survey C:
I'm actually trying to do some research on the differences of the 4 forms and possibly posting the results on my blog (https://itsudomo.wordpress.com).
For now, what I know is that Manhwa (comics by Koreans) and Manhua (comics by Chinese) were actually not originally published online and are not published as long strips but as books instead.
Webtoons became a form of Manhwa (so therefore, of Korean origin) that was created to meet the needs of the digital age. That's how long strips were created. The creators figured that scrolling vertically instead of flipping pages suited the digital needs of readers better.
Unfortunately for manhua, I'm still unfamiliar with its history hehe.