It kinda bothers me as well. People suddenly transforming into grammar-nazis just to appear more intelligent and authoritive.
To be honest, I don't give a shit. As long as we can understand you, write however you want. i cn undrstand if u wriet lyk this, and so can everybody else, so go ahead. I write like this on the forums to keep in touch with whatever old writing skills I might or might not have had before I got stuck chatting on irc, msn, message boards, online gaming, whatever.
but normally, i chat like this, and if you think that you're intelligenter hurr than me because you express yourself with grace and eloquence, get the fuck out.