There was a time, long long ago (however not in a place far far away; it was on this board, though in a previous incarnation), when a little bluelighter who called herself GhOst, was known to type lik dis and dat and wat eva. One day, her Uncle flip, candyflip to those who knew him not-so-well, decided that enough was enough. He told her she was a disgrace, that she was ruining the English language, and that she should put some effort into learning the language properly or by golly she'd get what for!
Well, little did Uncle flip know that our GhOst had quite a firm grasp of the English language. She went on to prove this fact by way of an exquisitely written retort, one which left not only no doubt that GhOst was capable of writing 'properly', but also showed that she was as accomplished as, if not better than, anyone else posting at that time. And certainly more than poor embarrassed candyflip.
Right. So the point of all that is, as Raz and others have mentioned, the way someone writes is
not a reflection of their intelligence. It may not even be a reflection of their true writing ability. GhOst wrote the way she did because it was easier. It was what she was used to because of time spent on IRC. And because
she knew people would understand her anyway.
So that's my second point, the same as made much more concisely by smileyfish, that being able to understand what's written is more important than perfect grammar and spelling.
But (OMG, he started a sentance with the word 'but'! *gasp*), I think it's just as important to be
able to write well. I don't care if someone makes a few mistakes, or doesn't capitalise at all, or even uses some IRCesque abbreviations, as long as they're
capable of writing 'properly'.
Me? I'm pedantic to the point of musty smelling, glasses-on-the-end-of-the-nose, disapprovingly frowning, tweed-jacket wearing, stuck-up obsessiveness. My SMS' usually take up exactly enough characters to fill up the entire SMS, with every word spelt correctly. I might throw in a smilie at the end though.