I question their selection
I seriously question their selection of "subjects". I would go so far as to say they started with their conclusion and worked backwards. Everyone I have seen using IM uses the abominable abbreviations such as "u", "r", "c", "1", "2", "4", "ne1", "2nite", "b4", "ur", "wut", "omg", "idk", "ppl"", "k" (instead of "ok"), "rofl", "roflmao", and a whole list of others that I don't even know (and don't care to know) like "rolfcopter". Sarah showed an example of that with "ZOMG" (what the hell does that mean?). That doesn't even get into the misspelling of words or the dreaded "prolly" which pops up on this site far too often.
As we've commented before, the fact that these youths are using this "style" to communicate with each other is bad enough. But some of them also use it in school papers and online learning (school/university) forums and message boards, and many of them use it when communicating (or attempting to communicate) with others.
I'm sorry, but I can never consider it a good thing when you lose the ability to effectively communicate with others.