IMO there are a lot of good "mangas" on the Internet, also a lot of terrible "mangas" (quotation marks because it's not really Japanese comic), and some sort of... Internet style? I don't know, here in Tapastic I see a bunch of popular comics which doesn't look like manga at all. Maybe they have strong influence, maybe even from anime and not manga, but... the narrative is different. I also see a lot of influence from western cartoons. I'm ok with it because I really enjoy the mix. And also I enjoy manga, but really, Japanese manga and webcomics I read are very different.
There's nothing wrong with manga anyway. It's bad when (young) people try to imitate and don't try to learn how to draw first, but when someone makes a comic that makes you wonder if it's really from the west or from a Japanese mangaka, what's the problem? :')
EDIT: Omg am I using replies the right way or what D: