I don't think it's so much an impediment to understanding as it is just fucking annoying. I can understand those abbreviations just fine, but my brain responds with what I can only describe as a mental gag reflex. I honestly despise it when people don't make the effort to type properly, and replacing numbers with letters, abbreviating words to phonemes, and refusing to capitalize or upsets me. I've been called a snob for saying this, but you know what? I like to write things so that other people can READ them, and I like it when others write things the same way.
On one hand, we are pretty much agreeing completely. I do not think that it is so difficult to spell things in their traditional forms that it should be the norm to abbreviate in text speak, and you agree that it is not a problem of understanding with most (not all because there are some ridiculous abbreviations out there) texting terms, but an act of laziness.
On the other hand I am confused that you say that you like to write things so that people can read them when you seem to agree with me that this shorthand doesn't actually stand in the way of actual understanding, and is a stylistic offence more than a specific grammatical one. If we were talking about messages that people would WANT to read, then we are pretty much in the same ballpark though, because I too find the extent to which this shorthand pervades our written culture.
Then again I was thinking "well, you're right, its more acceptable in mobile phone messages than in IM messages' but then I got to thinking how you'd define the standard of what formats it is ok to use it in and which it isn't. I can touch type quickly, sure, but I can also touch-text incredibly quickly as well, just through sheer force of habit. It's still slower than typing, but if we are going to use the speed of the medium as a gauge for how willing we should be to use shorthand, people would never write (pen to paper, I mean) in anything other than shorthand, since actual writing is fucking tedious unless you have a kind of fetish for it.
Then again I guess its a question of functionality. The only time I ever actually write anymore is in shorthand for work related purposes (6xTED, 4xWT, 8xSmrblk for req), because it's simply the easiest way to achieve what I have to. People who tend to use short hand in IM's are generally less interested in using the internet as a tool for discussion and more as a tool for a more superficial, banal kind of interaction, whereas people who type on IM programs like typical written English are probably more likely to treat it as an extension of physical social action.
Since text messages are typically a highly practical form of communication in order to exchange quick snippets of information about when you might meet someone, and for general sort of organisation of actual meat life happenings, the urge to use English in its traditional form would be rather lessened. I am quite willing to admit my distaste for text shorthand is more based on my fetish for language than it is for any practical reason. Also I kind of died a little bit when I saw the article on text speak in the newspaper, with an insert of a Shakespeare quote converted into this format. I understand the people who were writing the article were making a kind of joke I guess, but jesus, man,
too farTL;DR summary: i lik 2 hear myslf spk
type and am not actually arguing with anyone!