I think the whole "u" instead of "you" shows laziness or stupidity. I see it all the time in Ragnarok Online. There are some exceptions, like a friend of mine is from a foreign country, so I don't care how she types. Atleast she's trying.

I like what happened the other night. My friend and I were leveling with the help of a higher leveled wizard type guy. Over and over he kept calling us "noobs" and saying other things like "wtf u need 2 hit dat guy" My friend and I were both getting annoyed, so he said "We may be 'noobs' but at least we are literate." I think he confused the wizard, because all he could do was say "stfu noob".