I don't mind txt speak in a phone or other small device. You have a limited amount of space and the keyboards make typing everything out tedious. I still tend to do so, but I don't judge those who use txt speak as long as it's not in regular email.
Chris
I don't mind text speak on a phone either, up to a point. When it gets too hard to decipher I start to get irritated, especially if the text turns into a conversation requiring more than one or two replies. At that point I just call the person up and tell them to spit it all out so we're done in 30 seconds versus ten minutes of texting. Admittedly a lot of that is me, my big clumsy fingers on a phone keyboard, and being of the "get off my lawn!" age.
To Hawkmoon's point: Unfortunately I find myself doing the "there" and "their" thing all too often, and that's what I blame on me getting lazy because of autocorrect and spellcheck. They make it too (or to) easy for me to just hit "send", "post" or whatever and send a grammatically incorrect missive away.
Though part of that is me not caring as much about my grammar if it's a forum post or quick email or something. When I have to send "official" emails at work, or when I write most anything in Word as a letter, a report, or something going to publication, I do take my time and reread everything more than once to look for errors. If it's a work report or something for publication, I actually print out hard copies and sit down with a red pen, sometimes through several iterations to make sure I catch any little mistake that software misses.*
*ETA - even though official fed.gov policy now is we're supposed to do everything "paperless" and avoid printing stuff except for a limited set of criteria. I generally ignore the policy, because (again, possibly because of my age and what I'm accustomed to) I do a much better job of editing and reviewing things if I can lean back in my chair with my feet up on my desk and read the hardcopy. If I had to review stuff on screen only, I'd let a lot more errors slip by.