I try to keep quiet about grammar because some people just really don't get it.
But...some don't even try.
To/too/two
Your/you're
There/their/they're
I have a soft spot for affect/effect, who/whom, and a few others because I have a hard time with them.
I could care less. Makes no sense.
With internet chat in general, I don't like all caps, run-on sentences (even if you don't know where the period goes, try), or one long paragraph.
On another note, I have eye issues. Two of the fastest ways for you to get me to avoid reading your post would be to use really weird font that is hard to follow or colors that do not contrast well.