John McWhorter, writing in the New York Times , defends the new, casual modes of communication:
In an earlier America, then, one could hear speeches like William Jennings Bryans floridly oratorical, carefully written Cross of Gold speech given at the Democratic National Convention in 1896 (You shall not press down upon the brow of labor this crown of thorns. You shall not crucify mankind upon a cross of gold!) while ordinary people spoke much as we do today. The more anthropologically minded novelists depicted them doing it, such as Sinclair Lewiss street urchins in Main Street: Hey, lemmelone, Quit, dog-gone you, looka what you went and done, you almost spilled my glass swater. Gibbon is a distant presence here.
Fast forward to today, when we newly confront writing that seems much like the chatter of these pre-World War I street toughs, in its economy, spontaneity and even vulgarity. There is a virtual cult of concision OMG, LOL and such and little interest in the niceties of Strunk & White on capitalization or punctuation. We think of the elegant letters even modestly educated Civil War soldiers wrote and wonder how we got from I know I shall be thinking all the time If it was just my darling Loulie how different it would be to C U later.
Yet the brevity, improvisation and in-the-moment quality of e-mails and texts are those grand old defining qualities of spoken language. Keyboard technology, allowing us to produce and receive written communication with unprecedented speed, allows something hitherto unknown to humanity: written conversation. In this sense, they are not writing in the sense we are accustomed to. They are fingered speech.
More here .