Why do Latinoamericans write in all caps?

I mean, I'm kinda disappointed by this "JAJAJA ESTOY USANDO EL INTERNET" shit written always in ALL CAPS. Is there a reason behind this? Normal people would not do that.

youtube comments
serious business


No, seriously it is annoying. Notice how they'll write "jajajaja" even when the video has nothing to do with Spanish and the uploader doesn't speak it either.

Haven't seen it outside youtube though.