I personally am often distracted, at least, by the sloppy manner in which many people express themselves online. And, frankly, I get a bit sick of hearing the phrase...It's only the internet. When you're with a handful of friends who all express themselves that way, it's one thing. But, the internet is still a public venue for expressing your thoughts. If you want to be understood, you should speak clearly.
The type of stuff we've all seen out there is the internet equivilant of mumbling in a live vocal conversation. If someone doesn't care enough about what they're saying to make things clear, I don't tend to care enough about it to read it. That's especially true (as Drew and VC have stated) when the people using sloppy expressions claim to be superintelligent life forms. It's also heightened when those folks write something of greater length...whether it be a story or a post discussing something. Having at least one word per sentence misspelled, little or no punctuation, poor grammar and no paraghraph breaks makes it very difficult to read.
Having said all that, I also don't dislike those who do that or think ill of them. It's their choice to express themselves the way they want. I'm not going to tell them they have to do otherwise. But, if that kind of stuff is addressed to me, I tend to let them know that they shouldn't expect me to read or respond to it that way. That part is MY choice. I'm dyslexic to begin with. I don't need further things to screw with my brain when I'm trying to read something.
Ann